Prepare the Ricotta Mixture by combining ricotta cheese, Italian seasoning, garlic powder, salt, and pepper in a bowl.

Layer 1 cup of marinara sauce evenly across the bottom of the slow cooker.

Add half of the frozen cheese ravioli on top of the marinara sauce, followed by half of the cooked ground beef or Italian sausage, broken into small pieces.

Spoon half of the ricotta mixture over the meat layer, then sprinkle 1 cup of shredded mozzarella cheese on top.

Drizzle another cup of marinara sauce over the cheese layer and repeat the layering with remaining ravioli, meat, and ricotta mixture.

Pour the final cup of marinara sauce over the last layer and top with remaining mozzarella cheese and a sprinkle of grated Parmesan cheese.

Cover the slow cooker and set it to low heat, cooking for 4 to 6 hours until ravioli are tender and cheese is bubbling.

Let the lasagna sit for 10 minutes before serving, garnishing with fresh basil leaves.