Sweet and Sour Popcorn Chicken

I made this for my family and then for my Little Theater Class. It was a big hit both places. This could be used with pork instead of chicken also.

1 medium green pepper, cut into 1 inch pieces
1 small onion, thinly sliced
1 Tbsp vegetable oil
1 can (20 oz) unsweetened pineapple chunks
3 Tbsp white vinegar
2 Tbsp soy sauce
2 Tbsp ketchup
1/3 cup packed brown sugar
2 Tbsp cornstarch
1 pkg (12 oz) frozen popcorn chicken

In a large skillet or wok, stir-fry pepper and onion in oil for 3-4 minutes or until crisp-tender. Drain pineapple, reserving juice in a 2 cup measuring cup; set pineapple aside. Add enough water to juice to measure 1 1/3 cups, stir in vinegar, soy sauce and ketchup. In a bowl, combine brown sugar and cornstarch. Stir into pineapple juice mixture until smooth. Gradually add to the skillet. Bring to a boil; cook and stir for 2 minutes or until thickened. Add pineapple. Reduce heat; simmer, uncovered for 4-5 minutes or until heated through. Meanwhile, microwave chicken according to package directions. Stir into pineapple mixture. Serve immediately.
Serves 4