Preheat the oven to 350 F
Cook the spaghetti until al dente in a large pot of salted boiling water, according to package instructions. Drain and return to the pot. Mix in a cup of marinara sauce.
While the spaghetti is cooking, heat a large skillet over medium-high heat and brown the ground beef along with the onions and garlic until there is no pink left in the meat, about 4 minutes.
Pour in 2 cups of marinara sauce, one tsp Italian seasoning, ½ tsp red pepper flakes, ½ tsp of salt and pepper to taste. Cook for 5 minutes and set aside. This is your Bolognese sauce.
Mix the ricotta cheese, cream cheese, minced onion, dry parsley, garlic powder, one tsp Italian seasoning, ½ tsp salt, and pepper until smooth in a medium-sized bowl.
Assemble the casserole:- spray a 9x13-inch casserole dish with cooking spray and spoon half of the spaghetti into the bottom.- Spread the cheese mixture evenly over the spaghetti.- Add the remaining spaghetti on top of the cheese mixture.- Pour the bolognese sauce over the spaghetti. Sprinkle the shredded mozzarella cheese evenly on top and bake for 30 minutes until the cheese is melted and bubbly.