Heat 3 tbsp oil in a wok or large pan over high heat. Stir-fry eggplant until soft and golden, 5–6 min. Remove and set aside.
Add 1 tbsp oil to the pan. Fry garlic and ginger for 1 min, then stir in doubanjiang for another 1 min.
Add tofu, soy sauce, sugar, chili powder, and water. Cook 2-3 min. Stir in cornstarch slurry until thickened. Taste and season with salt if needed.
Return eggplant, toss to coat, and serve over rice. Finish with green onion + sesame seeds.
