Slippery yam soup(canh khoai mỡ) is a southern Vietnamese soup made with a certain type of yam known as khoai mỡ or slippery yam. The soup generally has a bright purple color from the yam.

Khoai mỡ means slippery root vegetable. It refers to a kind of yam which ranges in color from white to deep purple and is, in fact, quite slippery. The purple ones are more specifically referred to as khoai mỡ tím. These seem to be the same type of yam known as ube in the Philippines. In English they may be called slippery yam or purple yam or ube. Other root vegetables can be used in this recipe with similar results, such as the yam called khoai từ or even taro root.

To make the soup, first grate slippery yam. Some graters work well; the edge of a spoon or knife can also be used. The yam can also be sliced then smashed. It may also work to steam or boil the yam first and mash it, but in this case adjust the recipe accordingly.

Traditional recipes often add fresh or dried shrimp and fish sauce, though these can be optional. Mushrooms and mushroom stock can also be used for umami flavor in a vegan variation.

Serve seasoned and garnished with rice paddy herb, or let guests add pepper and herbs to taste. Lime juice and chili are also good additions.

Recipe

Ingredients

• 2 – 4 shallot
• 2 cup water or mushroom stock or other stock
• 1 slippery yam(khoai mỡ) or other yam, peeled and grated [substitute taro root]
• ½ tsp salt
• ½ tsp white pepper or black pepper
• 1 scallion, finely chopped
• 2 sprig rice paddy herb, chopped [substitute coriander]

Method

• saute shallot
• add water, yam
• simmer until thickened and fully cooked, about 20 minutes
• mix in salt, pepper
• garnish with scallion, rice paddy herb
• serve