1½ lbs boneless, skinless, chicken breasts, cut into 1" chunks
¾ c. cornstarch or tapioca flour
2 large eggs, lightly beaten
2 c. vegetable oil
¼ onion, chopped into chunks
½ red bell pepper, chopped into chunks
½ green bell pepper, chopped into chunks
Preheat oven to 325 degrees, lightly spray a 9x13 inch glass pan, set aside.
In a medium size mixing bowl (or a 2 c. measuring cup), whisk together the ketchup, brown sugar, Sriracha, oyster sauce, worcestershire, rice vinegar, chicken stock, black pepper, and red pepper flakes, set aside.
Place the cubes of chicken into a bowl with the whisked eggs, toss the chicken (taking care to let the egg drip off it) into a large Ziploc bag full of the cornstarch. Zip and shake until evenly coated.
Heat vegetable oil in a large saucepan or dutch oven. Working in batches (3-4), add the chicken and fry until golden brown and cooked through, about 1-2 minutes, then transfer to a paper towel lined plate.
Add the fried chicken to the prepared 9x13 pan. Whisk the cornstarch into the sauce and pour over the chicken, add the chopped vegetables and stir to coat. Place in the oven and bake uncovered for 50 minutes, stirring every 15 minutes or so. Remove and serve immediately.