1-1/2 cup elbow macaroni, uncooked
1 pound ground beef
2 tablespoons melted butter
1 cup sliced mushrooms
1 medium onion, chopped
1/2 cup chopped sweet red pepper
1 teaspoon salt
1/4 teaspoon pepper
1 can (16 oz.) diced tomatoes
1/4 cup butter
1/4 cup flour
2-1/2 cups milk
2 cups Jarlsberg cheese, shredded and divided
1 can (8 oz.) tomato sauce

Cook pasta according to package directions; drain and set aside. Brown meat in 2 tbsp. butter in skillet over medium heat, stirring to crumble. Add mushrooms and next 4 ingredients; cook until vegetables are tender, stirring often. Stir in tomatoes. Melt 1/4 cup butter in saucepan over low heat; add flour, stir until smooth. Cook 1 minute, stirring constantly.

Gradually add milk; cook over medium heat, stir until thickened and bubbly.

Stir in pasta and 1 cup cheese. Place half of pasta mixture in a greased 2-1/2 quart baking dish. Top with half of meat mixture and repeat layers. Top with tomato sauce.

Bake, uncovered, at 350°F for 25 minutes. Top with remaining 1 cup of cheese; bake additional 5 minutes. Let stand at least 5 minutes before serving.