To make the sauce
Mix all the ingredients mentioned for the sauce in a small sauce pan and bring it to a boil stirring well. Remove from heat and keep it aside. I did not have plum sauce, so I used the substitutes mentioned and it tasted great.
To marinate the tofu for Sweet and Sour Stir fry
Combine all the ingredients mentioned and make a smooth batter. The original recipe used one egg instead of water, but I used water to make the batter.
Drain the tofu and squeeze out all the excess water. Cut them into 1 inch cubes and then add it to the marinate batter. Use your hands and toss it well to combine. Keep it aside for at least 10 mins.
Heat oil in a frying pan to deep fry the tofu.
Combine all the ingredients mentioned under dredging the tofu. Add the marinated tofu to this mixture and toss it well. Shake off the excess flour and deep fry them until golden brown and crispy. Drain on a paper towel and keep it aside.
In a wok or a sauté pan, heat about 1 tbsp of oil. Sauté the onions and the chili pepper.
Now add the rest of the vegetables and sauté just until slightly tender.
Now add the prepared sauce and bring it to boil.
Add the fried tofu and pineapples and mix well. Add little water if needed to bring the sauce to required consistency. We like it a little bit on the runny side, so I added about a cup of water to give me enough gravy to serve with rice.
Simmer it for about 5 mins and then remove from flame.
Serve sweet and sour Stir fry hot with jasmine rice or any other fragrant rice of your choice.