Cut the chicken into bite sized pieces and seasoning them with ½ tsp salt.
Make the batter: place the flour in a medium bowl, add cornstarch, baking powder, water and cooking oil, and mix the batter until no lumps.
Mix the chicken with the batter.
In a large wok with oil that has been heated over medium-high heat, cook the chicken in batches, just until it is browned, not to cook it through.
Drain and set aside.
Bring up the oil temp with high heat and re-fry the chicken for 20 seconds.
This step is crucial to make the crust stays crispy and drive off excess oil. Drain and set aside.
In the same wok, combine your sauce ingredients – tomato paste, raspberry jam, water, sugar, white vinegar, and salt.
Bring to boil and add chopped bell peppers, onions, and cook for 20 second.
Thicken the sauce with cornstarch and water mixture.
Add the chicken back to the sauce in the wok, and stir fry to combine all together. Serve hot!