Saturday, February 23, 2008

Opo Squash Soup (Canh Bau Tom)

S wanted to try traditional Vietnamese dishes that people eat every day instead of the usual fare at restaurants in the US, so I thought I’d share with him a dish that my family eats at almost every meal—canh. Canh means soup in Vietnamese. A typical Vietnamese meal includes a meat/fish dish, a vegetable dish and some sort of canh. It can be made with a basic broth made from some sort of protein, usually shrimp or pork, and some kind of leafy green or squash. Vietnamese eat it by pouring some over a bit of jasmine rice. When I was growing up, the first thing I learned how to make was dipping sauce and the second was canh bau tom.

Opo squash (trai bau)


  • 2 tbsp extra virgin olive oil
  • ¼ tsp red chili powder
  • 3 shallots, sliced
  • 8 prawns, peeled & deveined
  • 1 Thai bird’s eye chili, sliced
  • 1 tsp ground white pepper
  • Fish sauce to taste
  • 6 cups water
  • 1 opo squash, cut into matchsticks
  • 2 scallions, sliced into rings
  • handful chopped cilantro leaves

It’s best to use prawns with heads because the prawn fat not only gives the broth a beautiful color but also makes it much more flavorful. When peeling prawns, carefully extract the fat into a bowl and discard heads, shells and veins. Slice prawns on bias or crush into chunky pieces. Place in the bowl with the prawn fat along with fresh chili, ground white pepper and fish sauce. Toss ingredients together and set aside to marinate while you prepare the rest of the ingredients.

There are different ways of cutting the opo squash for soup. I’ve seen it cut into cubes as well as thin semi-circular disks, but I prefer the matchsticks because they cook up in a flash and are much easier to eat. I also like to eat the skin on most fruits and vegetables, especially when it has not been waxed. The thin skin of the opo squash adds a nice taste and crunch, but you can peel it off if you wish.

Place soup pot over high heat and drizzle with a bit of olive oil. When oil is hot, throw in shallots and red chili powder. Toss until fragrant and put the prawns in. Stir quickly and as soon as prawns turn pink, pour in the water. I usually don’t measure the water, instead, I just eye it based on the size of the squash and how watery I want the soup. Bring water to a rolling boil and dump the squash into the pot. Always cook and reheat vegetables or vegetable soup uncovered in order to retain the freshness and beautiful green color. There is nothing worse than mushy, olive-colored vegetables! Give it a stir and adjust seasoning.

The soup is done when the opo turns a bit translucent. I like a bite to my opo, so I usually just take it off the burner as soon as the water starts to boil again. The opo will continue to cook in the broth even after you take it off the heat, so you don’t want to overcook it and have mush…unless you desire that texture. Immediately after taking it off the heat, add scallions and cilantro and give it a quick stir. You can eat this light and delicate soup alone or on top of a bit of jasmine rice.


emii said...

Quick question... do you know why some opo squash turns grey while cooking? I try to pick the younger squash w/ the finer hairs & littler seeds, but maybe have a 50% success rate w/ the grey factor.

Tia said...

Hi Emii,

Sorry for the late reply. I really don't know why your squash turns grey as that has never happened to me. I've used really young ones and older ones where the seeds are gigantic and the skin is tough with the same results. Having said that, I don't believe you are using opo squash/gourd because opo has completely smooth skin, no hair/fuzz at all. I would guess that you're using the oblong variety of winter squash, but even then, it shouldn't turn grey. Let me know if you ever find out! :)


hi tia
I've found your post, searching for any information about this (for me) strange vegetable. I was today going for a walk in the city (Barcelona) and in a quarter where a lot of foreign people live, I have found a little shop with vietnamese people. There was some things I've never seen before. One of them was the opo. I have asked what it was, but he has only told me its name:opo. And searching in internet, I have found your blog.
Thank you for the receipt. I have to decide what I will do with my opo.

Tia said...

Hi LocadeBarna,

The opo gourd is wonderful vegetable and tastes delicious in a stir-fry as well! Enjoy your opo. :)

Jennifer said...

Hi Tia,

I ran across this recipe (which sounds so yummy), but I have a question as to how I pick out the Opo squash. What should I look for in purchasing this unfamiliar veggie, and is it necessary to remove the seeds in preparing a dish with the Opo. Any help would be greatly appreciated, thanks for the awesome blog.

Tia said...

Hi Jennifer,

When picking out an opo gourd, look for smooth and unblemished skin. I love the smaller ones as I like to cook with the seeds. The seeds are perfectly edible, but can be a bit tougher in the bigger gourds. Cooking soup with the pith and seeds imparts a lovely, subtle sweetness. When stir-frying, treat it as you would a zucchini/courgette.


Anonymous said...

tried this today and it was delicious. next time i'll try cutting the opo into matchsticks as you suggest. thanks for posting this recipe.