Corned Beef & Cabbage with elbow

2 cups uncooked elbow macaroni 2 cups diced corned beef , cooked 3 cups finely chopped cabbage 3 tablespoons butter 1/2 cup chopped onion 3 garlic cloves ,[...]

nonstick cooking spray 1 1/2 cups dry elbow macaroni , uncooked 4 cups coarsely shredded cabbage 2 cups chopped leftover corned beef 1 small onion , chopped[...]