Heat a skillet over medium. Add the ground beef and cook until no pink remains, breaking it into small pieces as it browns.

Drain excess fat from the skillet. Return the beef to the pan.

Stir in the pasta sauce, garlic powder, and Italian seasoning. Let the sauce simmer 3 to 5 minutes to meld flavors.

Spray the slow cooker with nonstick spray or brush with a little oil. Spread a thin layer of the meat sauce across the bottom.

Arrange half of the frozen ravioli in a single layer over the sauce.

Spoon half of the remaining meat sauce over the ravioli. Sprinkle half of the mozzarella, half of the cheddar, and half of the Parmesan.

Repeat: another layer of ravioli, the rest of the sauce, then the remaining cheeses. Finish with a generous layer of cheese on top.

Cover and cook on low for 4 to 5 hours. Check near the 4-hour mark; the dish is ready when the ravioli are heated through and the cheese is melted and bubbly.

Let the lasagna rest 5 to 10 minutes before scooping to help it set. Serve hot.