This salty-sweet stir-fry calls on one of our favorite powerhouse ingredients: black bean sauce. Made from fermented and ground black soybeans, the Chinese condiment is earthy, deeply savory and packed with umami. Jarred black bean-garlic sauce is widely available in American supermarkets; look for it in the international aisle. We pair it with hoisin and Shaoxing wine (or dry sherry) to yield a flavor-rich blend, perfect for coating silky eggplant and tender-crisp bell peppers. We cook the eggplant and peppers in batches to avoid crowding the pan, which would cause the vegetables to steam rather than sear, and develop flavorful browning. Serve this as a side to any grilled, roasted or seared meat, poultry or fish, or over rice as a light vegetarian main.