Baked Ziti   Ingredients: 1 pound sweet Italian sausage, casing removed 1 medium red onion, diced 24 ounces homemade marinara sauce (Recipe) 2 cups shredded mozzarella cheese 16 ounces tube-shaped pasta (I used Ronzoni Garden Delight Penne Rigati), cooked al dente and drained per package directions 1/4 cup freshly grated Parmesan cheese, plus more for