In a large skillet over medium heat, cook the ground meat, diced onion, Italian seasoning, salt, black pepper, and garlic powder until the meat is no longer pink. Drain any excess grease if needed.

Stir in the pasta sauce and simmer for 2 to 3 minutes to combine the flavors. Set the empty pasta sauce jar aside for later.

Lightly coat the inside of a 6-quart crock pot with nonstick cooking spray.

Arrange a layer of broken oven-ready lasagna noodles across the bottom, then tuck in a few frozen cheese ravioli to fill the gaps.

Spoon a generous layer of the meat sauce over the pasta, spreading it evenly.

Sprinkle with mozzarella and Parmesan cheese.

Repeat the layers of noodles, ravioli, meat sauce, and cheese until all of the ingredients have been used, finishing with the remaining cheese on top.

Pour the water into the reserved pasta sauce jar, secure the lid, and shake well to loosen any remaining sauce. Pour the mixture evenly over the lasagna.

Cover and cook on LOW for 8 hours or HIGH for 4 hours, or until the noodles are tender and the cheese is melted and bubbly.

Let the lasagna rest for 10 to 15 minutes before serving.