Ravioli Lasagna

Name: Ravioli Lasagna
Prep time: 15 min
Cook time: 45 min
Total time: 1 h
Cuisine: European, Italian, Mediterranean
Ingredients: 1 pound ground Italian sausage; 1 small white onion, diced; 4 large cloves garlic, minced; 2 (28-ounce) jars good-quality marinara sauce; 2 (25-ounce) packages frozen ravioli; 1 (15-ounce) package ricotta cheese; 3 cups (12 ounces) shredded mozzarella cheese; toppings: freshly-grated Parmesan cheese and chopped fresh basil