Cook pasta in salted water according to package instructions until just aldente then drain (do not overcook since they will continue to cook in the oven).
In a deep pan or dutch oven, over medium-high heat, cook ground beef and onion, breaking up the beef with a spatula, until beef is fully cooked through and onions are softened (5-7 minutes). Add 1 tsp salt, 1/2 tsp pepper and sautee another minute. Add 4 1/2 cups of marinara, bring to a simmer and continue cooking 5 minutes then turn off the heat.
Spread a ladle of meat sauce over the bottom of a 9x13 casserole dish.
Into the remaining sauce, add in the ricotta. Add cooked pasta and stir just until noodles are coated (you want to keep that ricotta texture)
Transfer the pasta to the casserole dish. Top with shredded mozzarella and grated parmesan
Bake at 350˚F for 20-25 minutes. Let cool 5 minutes then serve. ENJOY!