Preheat the oven to 375˚F.
In a large skillet, over medium high heat, brown the ground beef and Italian sausage breaking up as you stir. Cook for 6-8 minutes, or until meat is cooked through. Drain any excess fat or liquid.
Stir in the marinara sauce.
In a medium bowl, make the cheese mixture by combining ricotta cheese, cream cheese, sour cream, and Italian seasoning and mixing until smooth.
Spread a few spoonfuls of sauce on the bottom of a 9x13 inch baking dish. Layer half the ravioli in the dish and flatten as much as possible. Pour half the remaining sauce on top of the ravioli. Then spread half of the cheese mixture over the sauce. Sprinkle half of the shredded cheese to finish the first layer.
Repeat this with the remaining half of the ingredients: ravioli, sauces, cheese mixture, and shredded cheese to finish.
Bake for 50-60 minutes, or until the casserole is hot throughout, the cheese is melted and the edges are bubbly.
