Add 1 ½ cups of uncooked rice to rice cooker. Cook according to package instructions. You can also cook on the stove.
Preheat the oven to 350°F. Cut 1 lb chicken breast into small bite-size pieces.
Add 1 lb of chopped chicken breast to a bowl along with ¼ cup cornstarch and toss together. Set aside.
In a small bowl combine the sauce ingredients: ¾ cup brown sugar, ¼ cup tomato paste, ½ cup lemon juice, 1 tablespoon soy sauce and 1 teaspoon garlic powder. Mix everything together and set aside.
Heat a frying pan (or oven-safe pot) with a bit of cooking oil on the stove. Once pan is hot, sear the chicken on each side for only 30 seconds. This is to help seal flavors in.
Remove from heat. Pour the sauce over the chicken and mix together. Transfer to an oven-safe dish if needed. Bake for 35-45 minutes, or until chicken is fully cooked. Stir the chicken halfway through baking.
Add cooked rice to a plate and top with the sweet and sour chicken. Optional toppings include green onion and sesame seeds. Serve and enjoy!