Slice the eggplant into 3 parts then halve each section of the eggplant. Or you can slice is on your desired shape and sizes.
Mix the soy sauce ingredients in a small bowl: soy sauce, water, oyster sauce, liquid seasoning, calamansi juice, sugar and pepper. Stir until the sugar is dissolved.
Slice the onions into rings and separate each layers. Take the large onion rings and set aside. Get the small ones for sauteing.
Heat a tablespoon of oil in a frying pan. Fry the onion ring lightly for a minute and set aside.
In the same pan, add more oil and Fry the eggplants until soft and brown. Put in a strainer and let is drain. Set aside.
In a wok, heat a small amount of oil and sauté onion and garlic until fragrant. Pour the soy sauce mixture and bring to a boil.
Add in the cornstarch slurry and stir until the sauce thickens. Add in the fried eggplants and stir for a minute. Then add in the onion rings and stir for a for a few seconds.
Serve hot with cooked rice.