2 tsp. olive oil
1 c. chopped onion
1/2 c. chopped carrot
1/2 c. chopped green pepper
1 1/2 c. chopped tomatoes
1 c. tomato sauce
1 1/2 tsp. chili powder
1 tsp. red wine vinegar
8 oz. lean ground beef
Salt and pepper to taste
4 (2 oz.) hamburger rolls, split and toasted

Brown beef in oil. Drain. Add remaining ingredients, cover and simmer for 20 minutes on low heat. Serve on toasted buns. 4 servings.