Preheat oven to 350 degrees. Lightly grease a 9x13 casserole dish.
Bring a large pot of lightly salted water to a boil. Place pasta in the pot and cook for 8-10 minutes, or until al dente, and drain.
In a skillet over medium heat, cook the sausage or ground beef until brown and drain grease.
Combine the cooked pasta and pasta sauce. Pour into casserole dish.
In a large bowl, combine the cottage cheese, olives, mushrooms and mozzarella cheese. Spread evenly over pasta and meat.
Top with pepperoni slices.
Bake for 25 minutes, or until bubbly and lightly browned.
Submitted by Tamara Santos - Finalist in the Favorite Casseroles Recipe Contest