Oven-Baked Sloppy Joe Dogs

1/4 C chopped onion
1 T butter
2 T brown sugar
1 C ketchup
1/2 C water
2 T vinegar
1 T Worcestershire sauce
1 tsp prepared mustard

Sauté onion in butter. Add everything else. Cook a few minutes. Split 12 to 24 hot dogs. Lay in a baking pan. Pour sauce overall. Bake at 350 degrees for 45 to 50 minutes.