Purple Yam Soup Recipe

5.0 from 1 vote

There are some days when you just need a bowl of something warm. Something soft. Something that doesn’t ask for much but gives everything. This purple yam soup recipe is exactly that for me.

I first learned this soup from my grandmother many years ago, back in the countryside. She would wake up early, when the morning light was still soft and grey, and start cooking before anyone else in the house opened their eyes. The sound of her moving around the kitchen, the gentle clink of the pot, the smell of something cooking slowly – that is what I remember most.

This purple yam soup is not fancy. It never tries to be. It is simple, honest food that has been cooked in Khmer homes for a very long time. The soup comes together with just a few ingredients, but somehow it tastes like so much more. The purple yam makes the broth thick and velvety, almost like it wants to wrap itself around you. The shrimp adds sweetness, and the herbs at the end bring everything to life.

If you have never cooked Khmer food before, please do not worry. I will explain everything slowly, the same way I would if you were standing right next to me in my kitchen. We will cook together, even if we are far apart.

Why You’ll Love This Soup

This soup is the kind of meal that makes you slow down. You cannot eat it quickly, and honestly, you will not want to. The broth is thick and comforting, the kind of texture that feels gentle going down.

The color is beautiful too. When the purple yam cooks, it turns the soup the softest shade of lavender. It is not bright or fake-looking. It is natural and quiet, like something nature made on purpose. My children used to love watching the water change color when I dropped the yam in. They would stand on their little chairs and peer into the pot, waiting for the magic to happen.

Another thing I love about this soup is how forgiving it is. If you add a little more water, it is okay. If you forget to buy basil, it is still good. The soup does not demand perfection. It just wants to be cooked with care.

It is also the kind of food that feels special but does not take all day. You can make it on a busy weeknight when you are tired. You can also make it on a quiet Sunday when you want to take your time. The soup will wait for you.

My Personal Experience

The first time I made this purple yam soup by myself, I was maybe nineteen years old. I had watched my mother and grandmother make it so many times that I thought I knew everything. But when I stood in front of the pot alone, my hands felt clumsy.

I remember grating the purple yam too fast and almost cutting my finger. I remember adding the shrimp and watching it turn pink, feeling so proud of myself. And I remember calling my mother right after, telling her the soup was done, and her laughing gently and saying, “Of course it is. You are my daughter.”

That is the thing about this soup. It carries memories. Every time I make it, I think about my grandmother’s hands, wrinkled and strong, holding the grater so carefully. I think about my mother teaching me how much fish sauce is enough, saying “just taste it, your tongue knows better than any measuring spoon.”

When I moved away from Cambodia, this was one of the first recipes I wrote down. I did not want to forget. I wrote it on a small piece of paper that eventually got splashed with water and stained purple. That paper is still somewhere in my kitchen drawer, folded and soft.

Now when I cook this soup for my own family, I watch my children’s faces as they take their first spoonful. They always smile. My youngest calls it “the pink soup” and asks for it when she feels sick or sad. I love that. I love that this soup has become part of their story too.

Easy-to-Find Ingredients

One thing that worried me when I first moved to a new country was whether I would still be able to cook the foods I grew up with. I remember walking through grocery stores looking for familiar things and feeling lost.

But this purple yam soup uses ingredients that are easier to find than you might think.

The purple yam itself is the star. You might need to visit an Asian market or an African market to find it, but it is worth the trip. Sometimes you will see it labeled as ube or purple sweet potato, but true purple yam is different. The skin is rough and brown, almost like tree bark. Inside, the flesh is beautiful purple. Some markets sell it already grated and frozen, which saves time. Both fresh and frozen work well.

Shrimp is easy to find anywhere. I like to use medium-sized shrimp and grind them myself at home, but you can also buy ground shrimp if you find it. The shrimp adds sweetness and makes the soup feel more substantial.

Everything else is simple. Fish sauce, green onions, black pepper, sugar, and basil. These are things you can find in almost any grocery store now. If you cannot find sweet basil, regular basil works too. If you cannot find basil at all, cilantro is also good.

The first time I made this soup for friends here, they could not believe how simple the ingredients were. They thought there must be something secret, something hard to find. But that is Khmer cooking. We let simple ingredients speak for themselves.

Ingredients List

1/2 pound (225 grams) shrimp – peeled, deveined, and ground or finely chopped
1/2 teaspoon salt
1/4 teaspoon black pepper
2 stalks green onion – chopped, divided in half
4 cups water
2 cups fresh grated purple yam – or 1 package frozen grated purple yam
2 tablespoons fish sauce
1 teaspoon sugar
1/3 cup chopped sweet basil leaves – optional but recommended

Why These Ingredients Are Used

Shrimp – gives the soup natural sweetness and makes it more filling. Ground shrimp also helps thicken the soup slightly.
Salt and black pepper – simple seasonings that wake up the shrimp and bring out its flavor.
Green onion – half goes into the shrimp mixture to keep it moist and fragrant. The other half goes on top for freshness at the end.
Water – clean and simple. You do not need broth because the shrimp and yam create their own flavor.
Purple yam – this is the heart of the soup. It releases starch as it cooks, making the broth thick and velvety. It also gives the soup its beautiful color.
Fish sauce – adds salty depth and that unmistakable Khmer flavor. It is the secret to making the soup taste like home.
Sugar – just a little to balance the salt and bring out the natural sweetness of the yam and shrimp.
Sweet basil – adds freshness at the very end. The smell of basil hitting the hot soup is one of the best parts.

Cooking Equipment Needed

Soup pot – any medium-sized pot works. I use a stainless steel pot that my mother gave me years ago. It does not need to be fancy.
Mixing bowl – a small bowl for mixing the shrimp with the seasonings.
Grater – if you are using fresh yam, you will need a grater. The small side with the finer holes works best. Please be careful with your fingers. I have learned this the hard way.
Wooden spoon – for stirring. Wooden spoons are gentle and will not scratch your pot.
Measuring cups and spoons – helpful but not required. After you make this soup a few times, you will know by look and feel.

Cooking Instructions

Before we start, let me tell you something my mother always said. Cooking is not about following rules exactly. It is about paying attention. Watch the pot. Smell the ingredients. Taste as you go. The recipe is your guide, but your senses are your teacher.

That said, let us begin.

First, take your shrimp and get it ready. If you bought whole shrimp, peel them and take out the dark vein running along the back. Then you want to grind or chop them until they are almost like a paste. You can use a food processor if you have one, or you can do what my grandmother did and chop by hand with a heavy knife. The texture does not need to be perfect. Small pieces are fine.

Put the ground shrimp in a small bowl. Add the salt, black pepper, and half of your chopped green onion. Use your fingers to mix everything together gently. Do not squeeze too hard. Just mix until everything is combined. Set this aside for now.

Next, look at your purple yam. If you are using fresh yam, peel off the rough brown skin. Be careful because the yam can be slippery. Some people like to wear gloves because the yam can make your hands feel itchy, but I have never had this problem. After peeling, grate the yam using the finer side of your grater. The pieces should be small, almost like shredded coconut.

If you are using frozen grated yam, just let it sit on the counter while you prepare everything else. It will thaw quickly.

Now take your soup pot and pour in the four cups of water. Put it on the stove over high heat and wait for it to boil. You will know it is ready when you see big bubbles breaking the surface and steam rising.

When the water is boiling hard, add your grated purple yam. Stir it well so it does not clump together. The water will start changing color immediately, from clear to pale purple to deeper purple. This is my favorite part. I always stop and watch for a moment.

Turn the heat down to medium and let the yam cook until it is tender. This takes about 10 to 15 minutes, depending on how fine you grated it. You can test by taking a small piece and pressing it with your spoon. If it squishes easily, it is done.

Now add the shrimp mixture. Drop it in by spoonfuls, or just dump it all in and break it apart with your spoon. Stir well. The shrimp will cook quickly, changing from grey to pink. This only takes two or three minutes.

When the shrimp is pink and cooked through, it is time to season. Add the fish sauce and sugar. Stir and then taste. This is important. Everyone’s taste is different. If you want it saltier, add a tiny bit more fish sauce. If it tastes too strong, add a splash of water and a pinch more sugar.

Turn off the heat. Add the rest of your chopped green onion and the chopped basil. Stir once more. The heat from the soup will soften the herbs but keep their fresh smell.

Your soup is ready.

Step-by-Step Directions

Prepare the shrimp – Peel, devein, and grind or finely chop 1/2 pound of shrimp.
Season the shrimp – In a small bowl, mix the ground shrimp with 1/2 teaspoon salt, 1/4 teaspoon black pepper, and half of the chopped green onion. Set aside.
Prepare the purple yam – If using fresh, peel and grate until you have 2 cups. If using frozen, thaw slightly.
Boil the water – Put 4 cups of water in a soup pot and bring to a rolling boil over high heat.
Cook the yam – Add the grated purple yam to the boiling water. Stir well. Reduce heat to medium and cook until yam is tender, about 10 to 15 minutes.
Add the shrimp – Add the seasoned shrimp to the pot. Stir and cook until shrimp turns pink, about 2 to 3 minutes.
Season the soup – Add 2 tablespoons fish sauce and 1 teaspoon sugar. Stir and taste. Adjust if needed.
Add the herbs – Turn off the heat. Stir in the remaining green onion and chopped basil.
Serve – Ladle into bowls and serve hot with rice.

Tips for Best Flavor

Grate the yam fresh if you can. Freshly grated yam gives the best texture and color. Frozen works, but fresh is special.
Do not overcook the shrimp. As soon as it turns pink, it is done. Overcooked shrimp becomes tough and rubbery.
Taste before adding more salt. Fish sauce is salty already. Always taste first.
Add herbs at the very end. This keeps their smell fresh and bright. If you cook them too long, they get dark and sad.
Stir gently but often. Grated yam can sink and stick to the bottom of the pot. A gentle stir now and then prevents this.
Let the soup rest for five minutes before serving. The flavors settle and come together during this time.
Use good fish sauce. This makes a real difference. Look for a brand that lists only anchovies and salt.

Variations and Adaptations

Use ground pork instead of shrimp – Pork makes the soup richer and heartier. Brown the pork first before adding water, or add it raw like the shrimp.
Add more vegetables – Some families add a handful of spinach or water spinach at the end. It wilts quickly and adds color.
Make it vegetarian – Skip the shrimp and use firm tofu or mushrooms instead. Use soy sauce in place of fish sauce.
Try different herbs – Cilantro, sawtooth herb, or even mint work beautifully. Use what you have.
Add a little coconut milk – For a creamier version, stir in a few tablespoons of coconut milk at the end. This is not traditional but very good.
Use chicken – Finely chopped chicken breast works well if you do not eat seafood.

Serving Suggestions

Serve hot with steamed white rice. The rice soaks up the thick broth perfectly.
Add a side of fresh vegetables. Cucumber slices or fresh herbs on the side are nice for contrast.
Eat it for lunch with leftovers. This soup is even better the next day, if there is any left.
Serve in small bowls as part of a bigger meal. In Cambodia, this soup would be one of several dishes on the table.
Top with extra fresh basil and a sprinkle of black pepper right before eating.

Storing Leftovers

Store in the refrigerator – Put leftover soup in a covered container and keep in the fridge for up to 2 days.
Reheat gently on the stove – Warm over medium-low heat, stirring occasionally. Add a splash of water if the soup has thickened too much.
Do not freeze – The yam texture changes when frozen and becomes grainy. This soup is best eaten fresh.
Keep herbs separate – If you know you will have leftovers, add fresh herbs only to the bowls you are serving. Store the plain soup separately.

Final Thoughts

This purple yam soup recipe is more than just food to me. It is a way of staying connected to where I came from. Every time I make it, I think about my grandmother’s kitchen with its old pots and the sound of chickens outside. I think about my mother’s hands and her patient way of teaching. I think about my children learning to love the same flavors I loved as a little girl.

If you are new to Khmer cooking, I hope this soup welcomes you gently. It is not complicated. It does not require special skills. It just asks you to take your time and pay attention. That is the Khmer way. We cook slowly because we believe food made with care tastes better. And it does.

If you enjoy this soup, you might also like my Khmer Pumpkin Pork Soup , which has the same comforting feel but with sweet pumpkin instead. Another favorite in our house is Bitter Melon Stuffed with Pork, which is a little more work but so worth it for special dinners.

For those who want to learn more about the ingredients we use in Khmer cooking, I recommend reading about Cambodian food culture from sources that respect our traditions. There is so much history in every dish.

Thank you for cooking with me today. I know life is busy and your time is precious, so the fact that you chose to spend some of it here, in my little kitchen, means so much. I hope this soup brings you warmth. I hope it makes your home smell good. And I hope, maybe, it becomes part of your story too.

Cook slowly, taste often, and share with people you love.

Frequently Asked Questions (FAQs)

Q: Is purple yam the same as sweet potato?

A: No, they are different. Purple yam comes from a different plant species. The skin is rougher, like tree bark, and the flesh is more starchy. Sweet potato is softer and less starchy. In America, grocery stores often label sweet potatoes as yams, but true yams are different .

Q: Where can I buy purple yam?

A: Look in Asian markets, Filipino markets (where it is called ube), or African markets. Some regular grocery stores with international sections also carry it. You can find it fresh or frozen .

Q: Can I use frozen grated yam?

A: Yes, absolutely. Frozen grated yam saves time and works very well. Just let it thaw slightly before adding to the pot .

Q: Why is my soup not turning purple?

A: There are a few reasons. Some yams have lighter flesh than others. Also, if you add too much water, the color will be paler. Next time, try using less water or adding more yam.

Q: Can I make this soup without shrimp?

A: Yes. Ground pork is a common substitute. Some families also use finely chopped chicken or just make it with yam only .

Q: Is this soup supposed to be thick?

A: Yes, that is normal. The yam releases starch as it cooks, which naturally thickens the broth. If you prefer it thinner, add more water. If you like it thicker, cook a little longer or add more yam .

Q: How do I grind shrimp at home?

A: You can use a food processor and pulse until finely chopped. Or you can chop by hand with a large knife, rocking it back and forth until the shrimp becomes paste-like.

Q: Can I leave the basil out?

A: Yes, the soup is still good without it. You can use cilantro instead, or just use extra green onion.

Q: How do I know when the yam is cooked?

A: Take a small piece and press it with your spoon. If it mashes easily, it is done. You can also taste a piece – it should be soft all the way through.

Q: Is this soup healthy?

A: Yes, it is quite healthy. It has protein from the shrimp, complex carbohydrates from the yam, and no heavy cream or oil. The yam also has natural steroids that some people believe help with energy, though I just eat it because I like it .