A typical component of an everyday Vietnamese meal, fragrant, wholesome, and fast soups like this one are called canh. Surprisingly, they’re typically made with water and rely on gently sautéed onion, salt, and fish sauce for foundational depth. What often defines canh is a ton of leafy greens, cooked in the pot to contribute their flavor and nutrients. A little protein is dropped in for savory flair. At the Viet table, canh is not just a first course—you can help yourself to it throughout a meal to refresh your palate. This nimble soup plays well with other dishes, but you can make a light meal of it, too. Just add warm bread and butter.

Instead of mustard greens, use another bold-flavored leaf, such as turnip greens or the radish tops left over from making pickles. Opt for spinach for a milder taste, or combine complementary greens, like kale and mustard.

As pictured, corkscrew-shaped shrimp result from halving them horizontally. Not fond of shrimp, or maybe it’s too expensive? Use a six-ounce fish fillet, such as tilapia or rockfish. Cut the fillet into bite-size pieces to add to the soup.