In a medium-sized non-stick skillet set to medium-high heat, add the ground beef and diced onion. Add the salt, pepper, garlic powder, and oregano. Cook until the meat is browned. Don’t drain all the liquid off the meat; keep a few tablespoons in the meat to keep it moist.
Spray the slow cooker with non-stick spray.
Add half of the marinara sauce to the bottom of the slow cooker.
Add HALF of the bag of ravioli on top of that sauce.
Add all of the ground beef mixture over the ravioli.
Add the remaining ravioli over the meat.
Pour over the remaining sauce.
Sprinkle over the mozzarella cheese.
Place the lid on the slow cooker. Cook on LOW for 4 hours.
Serve and enjoy!
