This is one of my husband's new favorites. Here it is:
2 cups spaghetti sauce
1 pkg. (25 ounces) frozen Italian sausage ravioli or ravioli of your choice
2 cups (8 ounces) shredded part-skim mozarella cheese
1 pkg. (10 ounces) frozen chopped spinach, thawed and squeezed dry
1/4 cup grated Parmesan cheese
Place 1 cup spaghetti sauce in a greased shallow 2-qt. baking dish. Top with half of the ravioli, mozarella cheese, spinach, and Parmesan cheese. Repeat layers. Bake uncovered at 350 degrees for 40-45 minutes or until heated through and cheese is melted.