Place tofu in a shallow dish with another heavy flat bottom dish on the top. Leave it for 10 minutes to press out all excess liquid. Drain and cut tofu into ¾ inch cubes.
Heat a tablespoon of oil in a non-stick fry pan. Pan fry cubed tofu on all sides until golden brown. This should take about 8 to 10 minutes. Remove and set aside.
Add remaining 3 tablespoons vegetable oil to a medium sized pot. Stir fry onion, garlic, and ginger over medium heat for 2 minutes.
Add curry powder and continue to fry for another 3 minutes. Pour in coconut milk and bring it to a boil.
Add Thai and Chinese eggplants. Cover, reduce heat, and allow eggplants to cook for 5 minutes.
Add pan fried tofu and salt. Cook for another 3 minutes.
Turn off stove and allow curry to sit for 10 minutes before serving.