This is an EASY Canh Khoai Mỡ recipe for the creamiest Purple Yam Soup. Gorgeously thick and packed with flavor, our hearty Vietnamese favorite has added garlic fried prawns and silky fish to leave you feeling 100% satisfied!
A stunningly creamy Vietnamese classic
Canh Khoai Mỡ must be one of the most unique Vietnamese soups ever to exist. If you think of Stuffed Bittermelon Soup (Canh Khổ Qua), Pork and Prawn Clear Noodle Soup (Hủ Tiếu Nam Vang) or Chicken Tapioca Noodle Soup (Bánh Canh Gà), they’ve all got one thing in common – a light and simple bone stock as the base.
But for this Purple Yam Soup, its thick and decadent texture is what makes it SO glorious.
The dish’s name is entirely fitting – khoai represents all root vegetables while mỡ refers to fat. What you get when you indulge in this recipe is a buttery and velvet melt-in-your-mouth experience.
Purple yam doesn’t come with much taste, so it’s ideal to enhance its earthiness with naturally sweet prawns fried in aromatics. Better yet, add another level of flavor with succulent fish slices.
You won’t regret trying this homemade Canh Khoai Mỡ, especially when it comes out vibrant and glistening!
Everything you need to know about the root vegetable
What is purple yam?
Vietnamese yam (khoai mỡ), also known as yampi root, is a starchy root that originates from Central America and the Carribean. The flesh color comes in many varieties, ranging from white to pink to purple and sometimes even a blend of all three.
Yampi root is not to be confused with taro or ube.
Unlike taro and ube, you’ll find that the taste is quite bland and the texture a firm but slippery one, much like okra. Because there isn’t much flavor to the root itself, it’s perfect for savory dishes.
What is purple yam good for?
Yampi root, much like many roots, is predominently made up of starch. However, it does also have fibre, which is great for digestive health. It is also known to contain calcium, protein, iron and vitamin C.
Why this recipe works
- Frying the prawns with aromatics infuses garlic and onion flavor into the meat.
- Adding sliced fish means extra texture and nutrients to a hearty soup.
- Using chicken stock as the base adds a layer of umami that can’t be achieved with water alone.
What you’ll need
Yams come in the white and purple variety, which can be found in Asian grocery stores. To check for the color, gently pierce the skin and peel a small portion back.
We used ling fish for this recipe, but any white fleshed fish will work well.
How to make this recipe
Deshell and devein the prawns, then cut them into 1 cm (0.4″) chunks. Thinly slice the fish into 1/2 cm (0.2″) thick pieces.
Halve the yams and use a spoon to scrape the flesh out.
Tip: Scrape using short and fast strokes. Using long strokes will result in long separate strands rather than a creamy texture when cooked.
Heat up a pot with oil and lightly brown the garlic and spring onion heads.
Brown the garlic and white spring onion heads on a medium heat with oil, then add the prawns to cook for 2 minutes or until just cooked. Transfer onto a bowl or plate.
On high heat, fill the pot with water and add the scraped yam in along with the water, fish sauce, salt and chicken bouillon powder.
Add the fish in to cook before pouring in the prawns and cook the soup for 30 minutes on a medium heat or until it reaches the desired consistency.
Tip: Make sure to continuously stir the pot, otherwise the soup will stick to the base and burn.
Garnish with pepper, roughly chopped coriander and rice paddy herbs, then serve immediately as is!
FAQs
If you can’t find the purple variety, they are sold frozen in packets in Vietnamese grocery stores. Otherwise, white yams work just as well!
You can get purple sweet potatoes, which might appear to be similar. However, sweet potatoes and root yams are not the same. Sweet potatoes are much sweeter and have a powdered texture while yams are slimey and much blander in taste.
Yes! That’s the beauty of this Canh Khoai Mỡ recipe. The soup relies solely on the root’s cooked texture for its creaminess to develop.
Tips for the best results
- Leave the yam scraping to last. While it’s much easier to have all the ingredients prepped and ready before cooking, the root might start to brown if left out for too long. Try to keep the yam’s prep to the very end.
- Choose long, thick and wide yams. It’s much easier to scrape in one direction from a yam that’s uniform in size rather than trying to get the flesh out of many smaller parts.
- Adjust the water content to your preference. If you prefer a thicker consistency, use less water. Likewise, a runnier soup can be achieved using more water. Just make sure to season accordingly!
Warm up the family with these nutritious soups!
- Fish Maw Soup – Thick, hearty and deliciously warming, there’s nothing quite like having this soup during a celebration with your loved ones.
- Chinese Fish Soup (魚頭爐) – Lightly tangy, savory and crunchy from the vegetables, you can enjoy this dish with noodles or simply as is.
- Chinese Watercress Soup (西洋菜汤) – One of my favorite soups from Grandma’s collection, this recipe uses Cantonese slow-cooking techniques for a highly nourishing bowl.
- Chicken Feet Soup (雞腳汤) – You won’t be short of collagen after a serving of Chicken Feet Soup. It’s a melt-in-your-mouth experience that everyone needs to try!
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Canh Khoai Mỡ (Creamy Purple Yam Soup)
Ingredients
- 1 1/2 kg / 3.3 lb purple yam (we get them from the local Asian supermarket)
- 100 g / 0.22 lb ling fish
- 400 g / 0.88 lb prawns
- 1.7 L / 7 US cup water/chicken stock/vegetable stock
- 1 tbsp chicken bouillon powder
- 1 tsp salt (or to taste)
- 1 tbsp fish sauce
- 4 cloves garlic (finely chopped)
- 8 white spring onion heads (get these by cutting the green part and roots off the spring onions)
- 2 tbsp oil
- pepper (for garnishing)
- coriander (for garnishing)
- rice paddy herbs (for garnishing)
Instructions
- Deshell and devein the prawns, then cut them into 1 cm (0.4") chunks. Thinly slice the fish into 1/2 cm (0.2") thick pieces.
- Halve the yams and use a spoon to scrape the flesh out.Tip: Scrape using short and fast strokes. Using long strokes will result in long separate strands rather than a creamy texture when cooked.
- Heat up a pot with oil and lightly brown the garlic and spring onion heads.
- Brown the garlic and white spring onion heads on a medium heat with oil, then add the prawns to cook for 2 minutes or until just cooked. Transfer onto a bowl or plate.
- On high heat, fill the pot with water and add the scraped yam in along with the water, fish sauce, salt and chicken bouillon powder.
- Add the fish in to cook before pouring in the prawns and cook the soup for 30 minutes on a medium heat or until it reaches the desired consistency.Tip: Make sure to continuously stir the pot, otherwise the soup will stick to the base and burn.
- Garnish with pepper, roughly chopped coriander and rice paddy herbs, then serve immediately as is!
Notes
- Leave the yam scraping last. While it's much easier to have all the ingredients prepped and ready before cooking, the root might start to brown if left out for too long. Try to keep the yam's prep to the very end.
- Choose long, thick and wide yams. It's much easier to scrape in one direction from a yam that's uniform in size rather than trying to get the flesh out of many smaller parts.
- Adjust the water content to your preference. If you prefer a thicker consistency, use less water. Likewise, a runnier soup can be achieved using more water. Just make sure to season accordingly!
- Yams come in the white and puruple variety, which can be found in Asian grocery stores. To check for the color, gently pierce the skin and peel a small portion back.
- We used ling fish for this recipe, but any white fleshed fish will work well.
I’ve never tried purple yams! That looks so interesting. I’m going to have to see what I can find at market. Thank you for all the tips!
I hope you do find it because it’s well worth the cook! You’re very welcome, Christian!
It is so hard to find great Vietnamese food where I live. Your recipes make it so easy to make my favorites at home! Thank you for such a detailed and delicious recipe!
You’re very welcome, Elizabeth! I hope you enjoy making all the Vietnamese dishes!
Love the colour of this soup and the addition of the fish sounds delicious.
Thanks, Amanda!
I LOVE purple yam – I usually just roast them or use them for desserts! This is such a cool idea!
Roasting purple yam is so delicious! This purple yam isn’t the roasting type, but it great in this soup! 😀