Brown and drain the ground beef or Italian sausage.
Spread a thin layer of marinara sauce in the bottom of the slow cooker.
Place a layer of frozen cheese ravioli over the sauce.
Add a layer of browned meat, sprinkle with Italian seasoning, and top with diced tomatoes.
Cover with mozzarella and Parmesan cheeses.
Repeat the layers until all ingredients are used, ending with cheese on top.
Cook on low for 4-6 hours or until ravioli is tender and cheese is bubbling.
Let it sit for 10 minutes after turning off the cooker for easier serving.
Serve hot, garnished with fresh basil leaves if desired.
Enjoy your Slow Cooker Ravioli Lasagna with your chosen accompaniments for a delightful meal that brings the essence of Italian comfort food to your table.