It is odd that the bright, yellow mustard we squirt on hotdogs comes from a bushy, green plant. There are actually dozens of different varieties of mustard plants, but the three most common are Brassica juncea (brown mustard), B. nigra (black mustard), and B. alba (white mustard). To make the familiar condiment, mustard seeds are typically soaked in vinegar and then blended to a smooth consistency, perfect for spreading on sandwich bread. Perhaps most surprising of all is that this same plant also has edible leaves -- and they are quite tasty.
Mustard greens do have some spunk, though their flavor is subtler than the bracing, peppery flavor of the seeds. The younger the greens are, the milder they taste. I like to toss the smallest leaves into salads to add an unexpected kick, and cook the biggest ones in bacon fat to serve alongside roast chicken.
Mustard greens are often sold in Asian markets, where they might be labeled by their Cantonese name, gai choy. They are popular in Indian cuisine as well, and particularly delicious in a Punjabi dish called sarson ka saag, in which the greens are well spiced and traditionally served with warm, buttered naan. In the United States, mustard greens are most common in the Southern states. Simmered slowly with a piece of ham hock, the greens lose their bitterness and become soft and sweet. The broth left behind in the pot-- called pot liquor or pot likker in some Southern kitchens -- is packed with water-soluble nutrients such as vitamin C. According to many, wise Southern grandmothers, pot likker "will cure what ails you." Mustard greens are an excellent source of vitamins K, A, and C, plus folate, manganese, fiber, and calcium.
Now that the weather is cooling down, mustard greens are appearing by the bunch in markets and will stick around through the fall and winter months. The leaves can be flat, lacy-edged, or ruffled. Give them a try, and see if they don't surprise you with their vivacious spirit.
Wonton Soup with Mustard Greens
The Cantonese word "wonton" means "swallowing clouds." To achieve this dreamy texture, each silky dough wrapper should hold less than a teaspoon of filling. These wontons are meant to be smaller than the dumplings found in most Chinese-American soups. Because the base of this soup is just chicken broth, use good-quality broth for best results.
½ pound (about 15 small) shrimp, peeled and finely chopped
½ pound ground pork
1¼ teaspoons minced garlic
2 tablespoons grated fresh ginger
1 scallion, white and light green parts thinly sliced, plus more for serving
¼ cup roughly chopped cilantro leaves, plus more for serving
½ cup finely chopped trumpet mushrooms
3 tablespoons minced shallot
2 tablespoons vegetable oil
1 teaspoon sesame oil
½ teaspoon crushed red pepper flakes
1½ tablespoons soy sauce
1½ teaspoons rice vinegar
75 round or square wonton wrappers
Cornstarch, for dusting
8 cups good-quality chicken broth
4 cups sliced mustard greens
In a large bowl, combine shrimp, pork, garlic, ginger, scallion, cilantro, mushrooms, shallot, both oils, red pepper flakes, soy sauce, and rice vinegar. Using your hands, mix well.
To form each dumpling, place 1 teaspoon of filling in the center of a wonton wrapper. Dip your finger in water and trace it along the edge of the wrapper to moisten. Fold in half, enclosing filling, and pinch to seal. Place dumpling on a baking sheet dusted with cornstarch; cover with a damp kitchen towel. Repeat with remaining wrappers and filling. (Wontons can be made 1 day ahead and refrigerated, covered tightly with plastic. They can also be frozen for up to 1 month in an airtight container. If making ahead, just add the dumplings directly to the boiling broth without defrosting and cook them for 2 minutes longer.)
Bring chicken broth to a boil in a large pot. Add mustard greens and wontons. Stir gently and adjust heat so that the broth simmers for about 5 minutes, or until the wontons are cooked through. The dumplings will float to the surface and begin to look wrinkly.
Ladle the soup into bowls. Sprinkle each bowl with a few cilantro leaves and sliced scallions. Serve immediately.