1 pound boneless skinless chicken thighs, cut into chunks
1-1/2 cups sliced fresh mushrooms
1 small onion, cut into wedges
2 tablespoons hoisin sauce
2 tablespoons prepared mustard
2 tablespoons sriracha Asian hot chili sauce or 1 tablespoon hot pepper sauce
1 package (14 ounces) potsticker dumpling wrappers
1 egg, lightly beaten
1 cup soy sauce
1 green onion, chopped
1 teaspoon ground ginger
In a food processor, combine the uncooked chicken, mushrooms, onion, hoisin sauce, mustard and chili sauce; cover and process until blended.
Place 1 tablespoon of chicken mixture in the center of each wrapper. (Until ready to use, keep wrappers covered with a damp towel to prevent them from drying out.) Moisten edges with egg. Bring opposite sides together to form a semicircle; pinch to seal.
Place potstickers in a single layer on a large greased steamer basket rack; place in a Dutch oven over 1 in. of water. Bring to a boil; cover and steam for 8-10 minutes or until filling juices run clear.
Meanwhile, in a small bowl, combine sauce ingredients. Serve with potstickers. Refrigerate leftovers.