Fry tofu until golden brown in color.
Transfer to a plate and set aside.
Drizzle some cooking oil in a pan and sauté onions.
Add in red and green bell pepper once onions are translucent. Stir fry.
Pour in water, vinegar and pineapple syrup. Mix.
Add in sugar and ketchup and mix well.
Stir in oyster sauce and bring to a boil.
Prepare a cornstarch mixture by mixing water with cornstarch.
Pour cornstarch mixture in the sauce.
Add in pineapple and mix.
Season with a dash of black pepper.
Pour sauce over fried tofu.
If preferred, garnish with sesame seeds on top.
Serve and enjoy.