Step 1

Place a rimmed baking sheet in the center of the oven and preheat to 475 degrees F. The baking sheet should be very hot, so keep it in the oven for about 30 minutes.

Step 2

Toss the Brussels sprouts with 2 tablespoons neutral oil and 1 teaspoon kosher salt in a large bowl until evenly coated. Lay the Brussels sprouts cut-side down on the hot baking sheet and bake until the outer leaves are lightly charred, the cut sides are browned and the sprouts are just tender in the center, 20 to 24 minutes.

Step 3

Meanwhile, make the sauce by mixing cornstarch with 3/4 cup cold water in a small bowl until combined and set aside.

Step 4

Heat the remaining 1 tablespoon oil in a medium saucepan over medium heat until shimmering. Add the garlic, dried Thai chiles, ginger and scallion whites over medium heat until the scallion is translucent and the garlic begins to brown, about 1 minute. Add the Sichuan pepper and stir until fragrant, about 30 seconds. Add the light soy sauce, dark soy sauce, oyster sauce, vinegar and brown sugar and cook until it starts to bubble, about a minute. Whisk in the cornstarch slurry and cook until the sauce thickens. Taste and adjust for seasoning with salt if needed.

Step 5

Toss the roasted Brussels sprouts, sauce, half the chopped peanuts and half the reserved scallion greens in a large bowl until evenly combined. Transfer to a serving platter and garnish with remaining chopped peanuts and reserved scallion greens.