01 - Toss eggplant batons with salt and let stand for 10 minutes. Rinse and pat dry thoroughly with paper towels.
02 - Heat 3 tablespoons of vegetable oil in a wok or large skillet over medium-high heat. Fry eggplant pieces for 6 to 8 minutes, turning until golden and soft. Remove and transfer to paper towels to drain excess oil.
03 - Wipe out excess oil from the pan, leaving 1 tablespoon. Add ginger, garlic, and red chili; stir-fry for 1 minute until fragrant.
04 - Add doubanjiang to the aromatics and cook for 1 additional minute, stirring constantly until the oil is deeply red and aromatic.
05 - Return fried eggplants to the pan. Add soy sauce, dark soy sauce, rice vinegar, sugar, and vegetable stock. Stir gently to coat evenly.
06 - Cover and simmer on low heat for 8 to 10 minutes, stirring occasionally, until the eggplant is very tender and flavors are well developed.
07 - Mix cornstarch and water to create a smooth slurry. Stir into the pan and cook for about 30 seconds until the sauce thickens to a glossy consistency.
08 - Drizzle sesame oil over the finished dish and garnish with sliced spring onions before serving.