Main Dish Casserole

1 pound ground turkey or beef
1/2 cup minced onion
1/4 cup chopped green pepper
2 tablespoons shortening
1 can tomato soup
2 cups cooked macaroni
1/2 cup shredded cheese
1 teaspoon prepared mustard

Melt shortening in skillet. Add meat, onion and green pepper. Cook, stirring until meat has lost its color and onion is transparent. Stir in remaining ingredients. Bake for 25 minutes at 375 degrees F.