Step 1

Beat ice water and egg together in a bowl using a whisk or a fork. Add baking soda and salt and mix to combine. Add 1 cup flour to water mixture; mix until blended but lumpy.

Step 2

Place remaining 1 cup flour in a separate bowl. Cover each piece of chicken in flour, then move to egg mixture and cover, letting excess batter drip off.

Step 3

Heat vegetable oil in a wok or large, deep frying pan over medium heat until a drop of water crackles when placed into oil.

Step 4

Place chicken into the hot oil and fry, flipping if needed, until no longer pink in the center and golden brown, 3 to 4 minutes. Set aside and keep warm.

Step 5

Combine cornstarch and 3 tablespoons water in a small bowl.

Step 6

Combine sugar, ketchup, vinegar, 1/2 cup water, orange marmalade, pineapple, pineapple juice, soy sauce, ginger, garlic, and red pepper flakes in a medium saucepan. Bring to a boil; add cornstarch mixture. Reduce heat and let simmer, stirring frequently, until desired thickness is reached.

Step 7

Pour sauce over chicken and serve.