Add eggplant into a large bowl and sprinkle with 2 teaspoons salt. Add tap water to cover and stir to dissolve the salt. Use a small plate or a lid to cover the eggplant pieces and submerge them in the water. Soak for 15 to 20 minutes.

Drain eggplant and dry thoroughly with a paper towel. Sprinkle with cornstarch and gently mix by hand, until the eggplant pieces are lightly coated.

Combine vegetable stock, light soy sauce, cooking wine, sugar, salt, and cornstarch in a small bowl. Mix well and set aside.

Heat a large pan (or a wok) with 1/3 cup oil over medium-high heat until hot. Place the eggplant in the pan and spread the pieces without overlapping. Cook the eggplant without moving it until the bottom turns golden brown. If the oil in the pan is fully absorbed by the eggplant before cooking through, add a bit more oil to the pan. Turn to medium heat when the pan start to smoke. Flip the pieces to cook the other side until golden brown. Transfer to a big plate.

Your pan should still have plenty of oil since the eggplant will start releasing oil once cooked.

Spread the potato pieces in the pan. Cook without moving until the bottom turns golden. Flip to cook the other side, until golden. Transfer to the plate with the eggplant.

If your pan still has too much oil, carefully remove some with a folded paper towel and only leave about 1 teaspoon oil in the pan.

Add green onion and garlic and stir a few times until fragrant.

Mix the sauce again to dissolve cornstarch completely. Pour into the pan. The sauce will thicken immediately.

Return the eggplant and potato to the pan and add bell pepper. Cook and stir until the sauce is evenly coated over the vegetables. Transfer everything to a plate immediately.

Garnish with sesame seeds (if using) and serve hot with steamed rice as a main or as a side.