Step 1

Cook 16 oz. fresh or dried wheat noodles in a large pot of boiling water according to package directions. Drain, reserving 1 cup noodle cooking liquid; set noodles aside.

Step 2

Whisk ⅓ cup oyster sauce, ⅓ cup soy sauce, 1 Tbsp. plus 1½ tsp. unseasoned rice vinegar, and 1 Tbsp. sugar in a small bowl until combined; set sauce aside.

Step 3

Separate dark green tops from white and pale green parts of 6 scallions; thinly slice tops and set aside. Thinly slice white and pale green parts.

Step 4

Cook ½ cup (1 stick) unsalted butter and white and pale green parts of scallions in a large skillet over medium-high, stirring often, until milk solids are golden brown and scallions are softened and starting to brown, about 4 minutes. Add 4 garlic cloves, finely chopped, 8 oz. snow peas, ¾ tsp. mild chile flakes, and most of reserved scallion tops. Cook, stirring constantly, until milk solids are deep amber in color and snow peas are bright green and just crisp-tender, about 1 minute.

Step 5

Stir in reserved sauce and bring to a simmer. Add reserved noodles and pour in ¼ cup reserved noodle cooking liquid. Cook, tossing often and adding more noodle cooking liquid as needed, until sauce is glossy and clings to noodles, about 1 minute. Taste and add more soy sauce if needed.

Step 6

Divide noodles among bowls and top with more mild chile flakes and remaining scallion tops.