Preheat Oven: Set oven to 350°F (175°C) to start heating.
Cut Chicken: Cube chicken breasts into bite-sized pieces.
Coat Chicken: Toss chicken in cornstarch, then dip in beaten eggs.
Bake Chicken: Arrange coated chicken on a baking sheet and bake until golden.
Make Sauce: Combine sugar, vinegar, soy sauce, ketchup, and garlic in a bowl.
Pour Sauce: Pour the sweet and sour sauce over the baked chicken.
Bake Again: Return to the oven and bake until the sauce thickens.
Stir Chicken: Stir occasionally to ensure even coating with the sauce.
Serve: Serve hot over steamed rice with a sprinkle of sesame seeds.