Barbecued Spareribs

This is Mom's recipe. To change it up a little bit we cut the meat into bite size pieces, that helps to remove a lot of the fat.

4 pounds spareribs
2 tablespoons margarine or butter
1/2 cup finely chopped onion
1 cup water
1 cup ketchup
2 tablespoons vinegar
2 tablespoons Worcestershire sauce
2 tablespoons brown sugar
1 teaspoon dry mustard
1 teaspoon salt
1/4 teaspoon pepper

Cut spareribs into serving size pieces. Brown slowly in two 10-inch skillets; put in a baking pan. Pour fat from skillet, melt butter, add onion and cook until tender. Add next nine ingredients, simmer 20 minutes. Set oven at 350. Pour sauce over ribs. Bake, covered, 1 1/2 hours.