Preheat the oven to 375 degrees F. In a large skillet or frying pan, brown the sausage over medium-high heat, using a spatula to crumble the meat to cook. Once cooked, drain to remove grease.
In the same frying pan, sauté onion in olive oil until translucent and soft, about 4 minutes. Add in garlic and sauté for another minute until fragrant.
Add the cooked sausage, seasonings, and half of the jar of marinara sauce to the pan and stir to combine. Remove from heat.
Lightly grease a 9x13 inch baking dish or casserole dish with nonstick cooking spray and spread a thin layer of the marinara sauce on the bottom of the dish. Arrange a layer of half of the ravioli over the sauce, then top with all of the sausage sauce, then half of the ricotta cheese, then half of the shredded mozzarella, half of the parmesan, repeat with the remaining ravioli, remaining marinara sauce, remaining ricotta, remaining mozzarella cheese, remaining parmesan cheese.
Loosely cover the dish with aluminum foil, be sure to avoid touching the cheese. Bake for 35 minutes, remove the foil and bake for 15 more minutes, then broil for 3-4 minutes to get the cheese a light brown and bubbly. Let the lazy lasagna sit for at least 10 minutes before serving.
Serve and sprinkle more parmesan cheese on top, garnish with fresh basil or parsley (optional). Serve while the cheese is melty and gooey. Enjoy!