Barbecued Ham Rolls

1/4 cup chopped onion

1/4 cup butter or margarine

1 cup chili sauce

3/4 cup water

2 tablespoons vinegar

2 tablespoons brown sugar

1 teaspoon ground mustard

1 pound shaved fully cooked ham

8 hamburger buns, split

In a large saucepan or Dutch oven, saute onion in butter. Add chili sauce, water, vinegar, brown sugar and mustard; bring to a boil. Reduce heat; cover and simmer for 20 minutes. Add ham; return to a boil. Reduce heat; cover and simmer for 10 minutes or until heated through. Spoon about 1/2 cup onto each bun. Serves 8.