• Step 1: In a large skillet, cook the ground beef or Italian sausage over medium heat until browned and crumbled, about 5-7 minutes. Drain any excess fat.
• Step 2: Add the marinara sauce and tomato sauce to the skillet and stir to combine. Reduce the heat and let the sauce simmer for 10 minutes, stirring occasionally.
• Step 3: In a medium bowl, mix together the ricotta cheese, 1 cup of the mozzarella cheese, Parmesan cheese, egg, oregano, and garlic powder. Season with salt and pepper to taste.
• Step 4: Spread a thin layer of the meat sauce in the bottom of a 6-quart crockpot. Arrange a layer of frozen ravioli on top, overlapping slightly. Spread half of the ricotta cheese mixture over the ravioli, then top with a layer of the remaining meat sauce.
• Step 5: Repeat the layers of ravioli, ricotta cheese, and meat sauce. Top with the remaining mozzarella cheese.
• Step 6: Cover the crockpot and cook on low for 4-6 hours, or until the cheese is melted and the edges are bubbling.