Cut the eggplant and onion into bite-sized pieces.
Slice the green onion thinly.
Add cooking oil to a pan and stir-fry the green onion over low heat until fragrant.
Add the onion and cook until it becomes translucent.
Add the eggplant, season lightly with salt and pepper, and stir-fry.
Pour in soy sauce, oyster sauce, and sugar, mixing well while stir-frying.
Once the eggplant is soft, place it over rice.