Prep the cabbage: Bring a large pot of water to a boil. Carefully peel 12–14 large leaves from the cabbage.
Blanch the leaves for 60–90 seconds until pliable, then transfer to an ice bath. Pat dry. Trim tough thick ribs with a knife so the leaves fold easily.
Mix the filling: In a bowl, combine ground chicken or turkey, breadcrumbs, egg, scallions, garlic, ginger, soy sauce, sesame oil, rice vinegar, cornstarch, salt, and pepper.
Stir just until combined. The mixture should be moist but hold together.
Form the dumplings: Lay a cabbage leaf flat. Spoon 2–3 tablespoons of filling near the base.
Fold sides inward and roll up snugly like a small burrito. Repeat with remaining leaves and filling.
Choose your cooking method: Broth-simmered (most flavorful): Bring the broth to a gentle simmer in a wide pot. Nestle dumplings seam-side down, cover, and cook 12–15 minutes, until the centers reach 165°F (74°C).
Steamed: Place dumplings in a steamer basket over simmering water.
Cover and steam 15 minutes.
Baked: Heat oven to 375°F (190°C). Arrange dumplings in a lightly oiled baking dish, brush tops with a bit of sesame oil, cover with foil, and bake 18–20 minutes.
Taste and finish: If simmered, ladle some hot broth over the dumplings to serve. Adjust seasoning with a splash of soy sauce or a squeeze of lime.
Add chili crisp, extra scallions, and sesame seeds if you like heat and texture.