Is for a Main Dish

For the Recipe Scavenger Hunt 2, I received the following recipes for the "Is for a Main Dish" category:

Cheese Mostaccioli Casserole

1 (16 oz) pkg mostaccioli noodles, cooked and drained
1 can cheddar cheese soup
1 jar spaghetti sauce
1 tsp pepper
1 tsp Italian seasoning
3 cup mozzarella cheese, shredded, divided

Combine noodles, soup, spaghetti sauce, pepper, Italian seasoning and 2 cups mozzarella cheese. Bake at 400 F for 25-30 minutes or until cheese melts and casserole is hot and bubbly.
You can also add: canned mushrooms, diced garlic, canned tomatoes or cooked ground beef or sausage.

Nacho Stuffed Shells

36 jumbo pasta shells (12-ounce package)
3/4 pound extra-lean ground beef
1 (1.25-ounce) package taco seasoning mix
1 cup water
1 (16 oz) refried beans with chilies
1 cup cheddar cheese, shredded
3/4 cup mild, medium or hot picante sauce
8-ounce can tomato sauce (a quality sauce makes a difference)
2-ounce can sliced ripe olives, drained
1/2 cup thinly sliced green onions
Optional Garnishes: sour cream, grated cheddar cheese, chopped jalapenos, chopped cilantro, salsa, guacamole

Preheat oven to 350 F. Prepare pasta according to package directions.
While pasta is cooking, saute the beef in a large skillet until browned; drain well. Add taco seasoning mix and water; simmer 5 minutes or until thickened. Stir in the beans and cheese. Cook until smooth and well mixed.
When the pasta is done, drain well. Fill the shells with beef mixture (1 to 2 tablespoons per shell). Combine the picante sauce and tomato sauce in sauce pan. Cook until heated, stirring occasionally.
Spread 1/2 cup of the tomato sauce over the bootom of a 9" x 13" baking pan that has been coated with cooking spray. Place filled shells side by side on top of sauce; pour remaining sauce evenly over shells. Sprinkle with olives. Cover with aluminum foil; bake 35 to 40 minutes or until thoroughly heated. Sprinkle with green onions.
Cover and let stand 5 minutes before serving. Serve immediately. Garnish as desired.