Cook the spaghetti noodles in boiling water according to the package directions. Cook them a few minutes less than the instructions because they will also cook and soften in the oven. Drain the noodles.
Once drained, toss in 1 cup of marinara sauce to coat the noodles.
Add the olive oil to a large skillet over medium-high heat. Add the ground beef and ground sausage and cook until the meat is no longer pink. Drain any excess oil.
Add the onion and garlic and cook for 3 minutes or until the onion is softened. Stir in Italian seasoning, salt, and pepper.
Turn off the heat and stir in 4 cups of marinara sauce.
Creamy Cheese Layer
In a large mixing bowl, add the cream cheese, sour cream, and ricotta cheese. Mix to combine.
Stir in the parmesan cheese and 1 cup of mozzarella cheese.
Preheat the oven to 350 degrees Fahrenheit. Spray a 9x13 baking dish with non-stick cooking spray.
Add the pasta mixture to the bottom of the prepared pan.
Evenly distribute the pads of butter on top of the pasta.
Spread the cream cheese mixture and top of the pasta mixture.
Add the meat mixture on top of the cheese mixture.
Sprinkle evenly with 1 1/2 cups of shredded mozzarella cheese.
Cover with foil and bake for 30 minutes.
Uncover and bake for an additional 10 minutes until the cheese is melted and bubbly!