Instructions

• Drain the pineapple chunks into a bowl, reserving the juice. Measure 1/4 cup of the reserved pineapple juice for the sauce and set it aside; keep the pineapple chunks separate.
• In a medium bowl whisk together 1 large egg white, 2 teaspoons cornstarch, and 1/4 teaspoon of the salt. Add the 1 pound chicken pieces and stir until evenly coated. Let sit 15 minutes at room temperature or cover and refrigerate up to overnight.
• In a second bowl whisk together the reserved 1/4 cup pineapple juice, 1 teaspoon grated fresh ginger, 1/4 cup white vinegar, 1/4 cup ketchup, 2–3 tablespoons brown sugar, the remaining 1/4 teaspoon salt, and 1–2 pinches cayenne pepper. Set the sauce aside.
• Heat a wok or large sauté pan over high heat. Test the heat by flicking a few drops of water into the pan; when a bead of water instantly sizzles and evaporates the pan is ready.
• Add 1 tablespoon of the oil to the hot pan and swirl to coat. Add the red and yellow bell pepper chunks in an even layer and stir-fry for about 2 minutes, until slightly tender but still crisp. Remove the peppers to a plate and wipe the pan dry with a paper towel.
• Return the pan to high heat. When hot (water test), add the remaining 1 tablespoon oil and swirl to coat the pan.
• Add the coated chicken pieces in a single layer, leaving space between pieces if possible. Let the chicken cook undisturbed for about 1 minute, until the bottoms are browned. Flip the pieces and cook the other side about 1 minute; the chicken may still be slightly pink in the middle at this point.
• Add the cooked bell peppers, the pineapple chunks, and the prepared sauce to the pan with the chicken. Stir to combine, then let simmer for about 2 minutes, stirring occasionally, until the chicken is cooked through (no longer pink in the center) and the sauce has thickened slightly.
• Remove the pan from the heat and let the chicken and sauce rest for a few minutes; the sauce will thicken as it cools slightly.
• Garnish with 1/2 tablespoon sliced green scallions if desired and serve warm (for example, over jasmine rice or as part of a multicourse meal).