Phase 1: Preparing and Baking the Chicken

1. Preheat & Prep Pan: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easier cleanup. For maximum crispiness, place an oven-safe wire rack over the parchment-lined baking sheet and lightly grease the wire rack with 1-2 tablespoons of oil. This allows air to circulate fully around the chicken. If you don’t have a rack, grease the parchment paper directly, but the bottom may not get quite as crisp.
2. Dry the Chicken: Pat the cubed chicken pieces thoroughly dry with paper towels. This is crucial – excess moisture prevents the coating from sticking properly and inhibits crisping.
3. Prepare Coating Stations: Set up two shallow bowls or plates. In the first, lightly beat the egg. In the second, whisk together the cornstarch, tapioca starch, white rice flour, salt, pepper, garlic powder, and onion powder until well combined.
4. Coat the Chicken: Working in batches (to avoid overcrowding), dip each piece of chicken first into the beaten egg, letting any excess drip off. Then, dredge the chicken thoroughly in the gluten-free flour mixture, pressing gently to ensure it adheres all over. Place the coated chicken pieces in a single layer on the prepared wire rack (or directly onto the oiled parchment paper), ensuring they are not touching. Overcrowding will cause the chicken to steam rather than crisp. You may need two baking sheets if necessary.
5. Optional Oil Drizzle: For extra crispiness and browning, you can lightly drizzle or spray the remaining 1 tablespoon of oil over the tops of the coated chicken pieces.
6. First Bake: Place the baking sheet(s) in the preheated oven. Bake for 15 minutes. Flip the chicken pieces carefully using tongs. Bake for another 10-15 minutes, or until the chicken is cooked through (internal temperature reaches 165°F/74°C) and the coating is light golden brown and feels dry and crispy to the touch. Total initial baking time will be around 25-30 minutes.

Phase 2: Making the Sauce and Finishing the Dish

7. Prepare the Sauce: While the chicken is baking, prepare the sweet and sour sauce. In a small saucepan, whisk together the pineapple juice, rice vinegar, water, brown sugar, (optional honey/maple syrup), gluten-free ketchup, gluten-free tamari (or coconut aminos), optional grated ginger, and optional minced garlic.
8. Heat the Sauce: Place the saucepan over medium heat. Bring the mixture to a gentle simmer, whisking occasionally until the sugar is fully dissolved.
9. Thicken the Sauce: In a separate small bowl, whisk together the 1 tablespoon of cornstarch and 2 tablespoons of cold water until smooth – this is your slurry. Slowly pour the cornstarch slurry into the simmering sauce while whisking constantly. Continue to cook and whisk for 1-2 minutes, until the sauce thickens enough to coat the back of a spoon. Be careful not to overcook, as it will thicken further upon cooling slightly. Remove from heat.
10. Taste and Adjust: Taste the sauce. Need more tang? Add a splash more vinegar. Sweeter? A touch more honey or sugar. Saltier? A tiny bit more tamari. Adjust to your preference.
11. Combine Chicken and Sauce: Once the chicken has completed its first bake and is crispy, carefully remove it from the oven. Let it rest for a minute or two. Transfer the crispy chicken pieces to a large bowl. Pour about two-thirds of the thickened sweet and sour sauce over the chicken and toss gently to coat evenly. Be gentle to maintain as much crispiness as possible.
12. (Optional) Add Veggies/Pineapple: If using bell peppers, onions, or pineapple chunks, you have two options:

    • Option A (Softer Veggies): Add them to the saucepan with the sauce during the last couple of minutes of simmering to soften slightly. Then pour the sauce and veggies over the chicken.
    • Option B (Crisper-Tender Veggies): Toss the raw veggies/pineapple chunks with the sauced chicken in the large bowl before returning to the baking sheet. They will cook slightly in the final bake.

13. Second Bake (Crucial Step): Spread the sauced chicken (and optional veggies/pineapple) back onto the wire rack/baking sheet in a single layer. Return to the 400°F (200°C) oven. Bake for another 8-10 minutes. This final bake helps the sauce adhere to the chicken, caramelize slightly, and sets the coating, preventing immediate sogginess. Keep a close eye to ensure the sauce doesn’t burn.
14. Rest and Serve: Remove the sweet and sour chicken from the oven. Let it rest for 5 minutes before serving. This allows the coating to firm up a bit more after the final bake. Serve immediately, drizzling any remaining sauce over the top if desired, and garnishing with toasted sesame seeds and sliced green onions.