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A ladle scooping into Canh Khoai Mỡ
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5 from 1 vote

Canh Khoai Mỡ (Creamy Purple Yam Soup)

This is an EASY Canh Khoai Mỡ recipe for the creamiest Purple Yam Soup. Gorgeously thick and packed with flavor, our hearty Vietnamese favorite will leave you feeling 100% satisfied!
Prep Time20 mins
Cook Time35 mins
Total Time55 mins
Course: Breakfast, Dinner, Lunch, Soup
Cuisine: Asian, Vietnamese
Servings: 8
Calories: 544kcal
Author: Jeannette


  • 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)


  • 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!


  • 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.


Calories: 544kcal | Carbohydrates: 106g | Protein: 19g | Fat: 5g | Saturated Fat: 1g | Cholesterol: 132mg | Sodium: 1058mg | Potassium: 3180mg | Fiber: 16g | Sugar: 2g | Vitamin A: 637IU | Vitamin C: 69mg | Calcium: 154mg | Iron: 3mg