Marinate the pork in sugar, salt, soy sauce and cornflour slurry. Let sit for 15 minutes.
Heat a large frying pan with oil over high heat. Saute the 1/2 tablespoon garlic and pork until cooked through; about 3-5 minutes.
Heat the same frying pan with oil over high heat. Saute the remaining garlic until aromatic; 2-3 minutes. Stir in the eggplant and water until tender; about 5-6 minutes.
Put the pork and eggplant into a saucepan. Add just enough water to cover the ingredients. Bring the mixture to the boil then turn the heat down to medium and simmer for 20 minutes.
Meanwhile, lightly coat the tofu in cornflour. Heat a frying pan with oil over high heat. Pan-fry the tofu until golden on both sides; about 3-4 minutes. Add to the saucepan in the last 10 minutes of cooking.
Make the sauce by mixing together the oyster sauce, sesame oil, black soy sauce, soy sauce and black pepper. Pour into the saucepan and stir. Garnish with spring onions before serving.
If egg tofu is unavailable, substitute in 250g plain tofu. Black soy sauce can be purchased in Asian speciality shops.