Rinse and devein shrimp, drain and set aside. Heat 2 Tbsp. butter in skillet and saute the onions and garlic til soft. Mix in the tomato sauce, ketchup, brown sugar, red wine vinegar mustard and chili powder. Cook uncovered over low heat 5 minutes. Add cleaned shrimp, mix and cook about 8 minutes til shrimp is cooked.
Put cooked rice on individual plates and spoon on sauce and shrimp mixture. Serve with Mexican style rolls or corn bread.