Step 1

Whisk cornstarch, soy sauce, vinegar, and 1 Tbsp. water in a bowl until smooth; set aside.

Step 2

Heat 1 tablespoon oil in a large skillet over medium-high. Add squash; cook, stirring often, until browned, about 4 minutes. Transfer to a large bowl. Add 1 tablespoon oil and eggplant to skillet; cook, stirring often, until lightly browned, 2 to 3 minutes. Transfer to bowl with squash.

Step 3

Add remaining 1 tablespoon oil, scallion whites, and jalapeño to skillet; cook, stirring often, until charred, about 1 minute. Add peanuts, garlic, and crushed red pepper; cook until garlic is fragrant, about 30 seconds. Return all vegetables to skillet. Add cornstarch mixture; cook, stirring constantly, until sauce thickens slightly and coats vegetables, about 2 minutes. Serve with rice and top with scallion greens.