Prepare the chicken: Cut the chicken breast into bite-sized pieces or strips. Remove any excess fat or connective tissue.

Season the chicken: In a large bowl, combine salt, ground black pepper, Chinese five-spice powder, and any additional seasonings of your choice. Mix well.

Coat the chicken: Add the chicken pieces to the seasoning mixture and toss until they are evenly coated. Let the chicken marinate for 10-15 minutes to allow the flavors to penetrate.

Heat the oil: In a large frying pan or a large wok, add enough cooking oil to deep-fry the chicken. Heat the oil over medium-high heat until it reaches around 350-375°F (175-190°C). You can test the temperature by dropping a small piece of chicken into the oil; if it sizzles and rises to the surface immediately, the oil is ready.

Fry the chicken: Carefully add the coated chicken pieces to the high temperature oil, making sure not to overcrowd the pan. Fry the chicken in batches if necessary. The frying time varies. Fry for about 4-5 minutes or until the chicken turns golden brown and crispy. Stir occasionally to ensure even cooking.

Drain excess oil: Once the chicken is cooked, use a slotted spoon to remove the cooked chicken from the oil. Place the fried chicken on a paper towel-lined plate or wire rack to drain excess fat.

Dump the deep frying oil leaving 2 tablespoons of oil in the wok. Heat oil over high heat, add chopped onion, and sauté for about 1 minute until fragrant.

Add the deep-fried chicken pieces and red and green pepper to the sauteed onion. Toss quickly for another 2 minutes. Sprinkle salt and black pepper over the chicken.