Cut the eggplant, bell pepper, and onion into bite-sized pieces.
Generously add cooking oil to a pan and heat it up.
Add the eggplant and stir-fry over high heat, then add the bell pepper and onion.
Add minced garlic and ginger, and stir-fry together.
Season with soy sauce, oyster sauce, and sugar.
Once the ingredients are cooked, finish with a drizzle of sesame oil.