Stir 2 Tbsp. oyster sauce, 2 Tbsp. sambal oelek, 2 Tbsp. unseasoned rice vinegar, 1 Tbsp. fish sauce, and 1 Tbsp. dark brown sugar in a small bowl to combine; set sauce aside.
Step 2
Heat 1 Tbsp. vegetable oil in a large skillet over medium-high until oil begins to smoke. Add two thirds of ½ medium head of green cabbage (about 1¼ lb.), cored, leaves cut into 2″ pieces, and cook, undisturbed, until dark brown and blistered in spots, about 3 minutes. Toss, add 1 Tbsp. vegetable oil and remaining cabbage and cook, tossing occasionally, until cabbage is lightly charred in spots and mostly wilted, about 4 minutes. Transfer to a plate; reserve pan.
Step 3
Meanwhile, mix 1 lb. ground chicken, beef, or pork, 1 Tbsp. vegetable oil, 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt, ½ tsp. baking soda, and remaining ½ tsp. dark brown sugar in a medium bowl until well combined.
Step 4
Heat remaining 1 Tbsp. vegetable oil in reserved pan over medium-high. Add chicken mixture and cook, breaking up any large clumps of meat with a wooden spoon or heatproof rubber spatula, until browned and nearly cooked through, about 5 minutes. Add 6 garlic cloves, thinly sliced, one 1″ piece ginger, peeled, very finely chopped, and most of 1 bunch scallions, thinly sliced, and cook, tossing often, until softened and very fragrant, about 2 minutes. Add reserved sauce and cook, tossing occasionally, until thickened, 1–2 minutes.
Step 5
Return cabbage to skillet and add 2 Tbsp. unsalted butter. Cook, tossing often, until butter is melted and cabbage is glossy, about 1 minute. Serve stir-fry topped with remaining scallions.
