Mushroom Ravioli and Sausage Casserole

Name: Mushroom Ravioli and Sausage Casserole
Ingredients: Kosher salt; 3 tablespoons unsalted butter; 1 onion, finely chopped; 10 ounces white mushrooms, thinly sliced; Freshly ground pepper; 6 ounces mild Italian sausage, casings removed; 3 cloves garlic (2 thinly sliced, 1 grated); 2 teaspoons fresh marjoram, chopped; 1 28-ounce can crushed tomatoes; 2 10-ounce packages refrigerated mushroom ravioli; 1 cup shredded mozzarella cheese; 1/4 cup breadcrumbs; 1 tablespoon chopped fresh parsley