For the Sweet and Sour sauce:

• Stir all the sauce ingredients together in a bowl and set aside.

For the chicken:

To pan fry chicken:

• Combine the egg whites and cornstarch in a medium sized bowl and whisk until thoroughly combined. Stir in chicken until all pieces are evenly coated.
• Heat a large pan over high heat. You want the pan to be nice and hot so the outside of the chicken browns and crisps, while the inside stays juicy.
• Add oil to pan, let it get hot, then add half of the chicken, dropping in the pieces one by one without the pieces touching each other. Don’t stir or move the chicken until a brown crust forms on the bottom.
• Flip the pieces so the other side browns. You can add an additional tablespoon of oil when flipping the chicken, if desired.
• Then stir the chicken so some of the sides turn golden. Cook until chicken is done inside.
• Remove chicken from pan and repeat with the second half of chicken.

OR

To deep fry the chicken:

• Whisk egg whites in a bowl or pie dish. Add chicken and stir until all chicken is coated.
• In a second bowl or pie dish, whisk cornstarch and baking soda to combine. Dredge the chicken pieces in the cornstarch until all surfaces are covered. I like to add half of the chicken at a time rather than piece by piece. This creates nubs of coating on the chicken that get crunchy when cooked. Place dredged chicken on a baking/cooling rack and repeat until all chicken is coated.
• Heat an inch of frying oil in a large pan over high heat until it reaches 380 F. The higher the sides, the less mess. A hot oil will let the chicken get a crunchy golden interior without overcooking on the inside. Hotter oil also means less oil absorbed by the chicken.
• Fry the chicken in batches, being careful to not crowd the pan, until golden brown on the outside and done inside. Place on a baking/cooling rack.

To finish:

• ( If you pan fried the chicken, you can use the same pan the chicken was cooked in. Wipe out any overly browned bits with a paper towel.)
• Cooking over medium high heat, put in a little oil, add the garlic and ginger, and stir for a few seconds. Add the onion and bell pepper and stir fry for about a minute. I like the onions and peppers to be tender-crisp and to keep their bright colors.
• Pour in the sauce and let it come to a boil. It will thicken in about a minute. Add the pineapple and cook until just heated, then stir in the chicken and turn off the heat. Sprinkle with sliced green onion, if desired, and serve.