Gather shallow bowls. Crack the eggs into the first bowl, and whisk until well combined with a fork.
2 eggs
Add the cornstarch to another bowl. Dip each piece of the diced chicken into the whisked egg, draining off any excess egg. Dip the chicken into the cornstarch and gently shake off any excess. Transfer to a plate.
1 cup cornstarch, 1 pound skinned boneless chicken thighs
Heat 2 tablespoons of the oil in a large skillet over medium-high heat.
3 Tablespoons vegetable oil
Cook the chicken in batches until golden brown on all sides and no longer pink inside. Set aside on a clean plate lined with paper towel.
Heat the remaining 1 tablespoon of oil in skillet. Add the onions and bell pepper and cook, stirring, for 3 minutes or until softened.
2 onions, 1 red bell pepper, 1 green bell pepper
Add the garlic and cook, stirring, for 1 minute or until the garlic is fragrant.
3 garlic cloves
Add the brown sugar, apple cider vinegar, reserved pineapple juice, tomato ketchup and oyster sauce.
⅓ cup brown sugar, ⅓ cup apple cider vinegar, ¼ cup reserved pineapple juice, ¼ cup tomato ketchup, 1 Tablespoon oyster sauce
Stir frequently until heated through.
Combine the 1 tablespoon of cornstarch with 2 tablespoons of water in a small bowl and stir until well combined.
1 Tablespoon corn starch
Add to the skillet and stir to combine.
Add the pineapple to the skillet along with the chicken.
1 cup chopped canned pineapple
Stir to combine, and simmer until heated through and the sauce has thickened.
Season to taste with salt and pepper.
salt and pepper
Garnish the chicken with sesame seeds, if using, before serving.
sesame seeds