Brown the Beef: In a medium non-stick skillet over medium-high heat, cook the ground beef and diced onion with salt, pepper, garlic powder, and oregano until the meat is thoroughly browned. Keep a bit of the liquid with the meat to maintain moisture.

Prep the Slow Cooker: Lightly spray the inside of your slow cooker with non-stick spray to prevent sticking.

Layer the Sauce: Spread half of the marinara sauce on the bottom of the slow cooker.

Add Ravioli: Place half of the frozen ravioli in a single layer over the sauce.

Layer the Beef: Evenly distribute the ground beef mixture on top of the ravioli.

More Ravioli: Add the remaining ravioli over the beef layer.

Top with Sauce and Cheese: Cover the ravioli with the rest of the marinara sauce, then sprinkle the shredded mozzarella cheese over everything.

Cook: Set your slow cooker to LOW and cook for 4 hours, until everything is bubbly and the ravioli is tender.

Serve this delicious slow cooker ravioli lasagna hot and enjoy a no-fuss, comforting meal that's perfect for any night of the week. This ingenious recipe not only simplifies the lasagna-making process but also brings a rich, cheesy, and savory delight to your dinner table with minimal effort.