If you want a layer of meat, brown in a skillet, drain and set aside.
Brush the bottom of a 9" x 13" casserole dish with spaghetti sauce. Top with 1 layer of frozen ravioli, not overlapping. Sprinkle cooked meat on top of that. Top with a mix of cheddar and mozzarella.
Top with the spaghetti sauce again and then the ravioli layer. Meat layer. Sprinkle with the remaining cheddar and mozzarella, cover dish with foil.
Place the baking dish in the oven and bake for 30 minutes. Remove foil during the last 10 minutes so the cheese can brown to golden brown.
When browned on the top remove and sit for 15 minutes before slicing and serving.