Step 1. Preheat the Oven: Set your oven to 350ºF. Lightly coat a 9x13x2-inch baking dish with cooking spray, then set it aside.
Step 2. Prepare the Meat Sauce: In a large skillet, cook the Italian sausage over medium heat until browned. Once done, drain off any excess fat. Stir in the spaghetti sauce and set aside.
Step 3. Mix the Cheeses and Ravioli: In a large bowl, mix together cottage cheese, softened cream cheese, sour cream, parmesan cheese, parsley, and garlic powder. Add the frozen cheese ravioli to the cheese mixture and toss until everything is evenly coated.
Step 4. Assemble the Casserole: Spread the ravioli mixture evenly in the bottom of the prepared baking dish. Pour the meat sauce over the top, then sprinkle mozzarella cheese over it.
Step 5. Bake: Bake the casserole uncovered for 45 minutes. After baking, let it cool for 10-15 minutes before serving to allow the flavors to come together.