1-First Step: Prep and marination Trim fat and any cartilage from 2 pounds of skinless boneless chicken breast. Butterfly each breast to about 1/2 inch thickness, then cut against the grain into finger-size strips. Put the strips into a large bowl and add 1 tablespoon Shaoxing rice wine, 1 teaspoon salt, and 1 large beaten egg, keeping about 2 tablespoons of that beaten egg reserved for the batter. Toss to combine, cover, and marinate for 10-15 minutes at room temperature, or up to overnight in the fridge for deeper flavor.

2-Second Step: Make the batter In a mixing bowl, whisk 2 cups self-rising flour, 2/3 cup cornstarch, 1/4 teaspoon baking powder (optional), and 1/2 teaspoon salt. Stir in 1 3/4 cups water and the 2 tablespoons beaten egg you reserved from marination until the batter is smooth. Add 2 tablespoons neutral oil and 1 teaspoon vinegar, mix briefly, and set the batter aside. Use this batter fresh just before frying for the best puff and crunch.

3-Third Step: Prepare the sweet and sour sauce Combine 1 1/4 cup water, 3/4 cup pineapple juice (or a 6 fl.oz can), 3/4 cup vinegar, 3/4 cup ketchup, 1 1/4 cup sugar, 1/8 teaspoon salt, and 3 to 5 drops red food coloring (optional) in a saucepan. Bring to a boil over medium heat, stirring until sugar dissolves. Reduce heat and slowly whisk in the cornstarch slurry (1 tbsp cornstarch mixed with 1 tbsp water) until the sauce thickens and becomes glossy. Keep warm on very low heat while you fry the chicken.

4-Fourth Step: Frying technique for a puffy, crispy crust Heat 2 to 3 inches of neutral oil in a wok or heavy pot to 350°F. Mix the marinated chicken so it is evenly coated, then add batter and stir until each piece is fully covered. Fry in small batches so the oil temperature stays steady. Fry each batch for 4 to 5 minutes until the pieces float and are pale golden. Use a toothpick or skewer to handle pieces to avoid missing batter spots. Drain on paper towels and rest 5 minutes, then fry a second time at 350°F for 3 to 4 minutes until golden brown and extra crispy. Drain excess oil.

5-Final Step: Vegetables, toss, and serve Blanch the vegetables to keep them clean and crisp: drop 1/2 bell pepper and 1/2 large carrot into boiling water for 15 seconds, then add the 1/4 small yellow onion for another 5 to 10 seconds. Drain immediately. Toss the fried chicken, blanched vegetables, and 1 cup pineapple chunks together in a large bowl. Serve immediately with the sweet sour sauce poured over or served on the side for dipping.