Directions:

Heat 2 tablespoons of oil in a 12-inch skillet over medium-high heat. Add ground beef or turkey; cook until well browned on all sides. Remove meat to a medium bowl with a slotted spoon. Add onions and garlic to pan drippings and cook for 5 minutes or until tender. Add crushed tomatoes, basil, salt, and cooked ground meat. Heat to a boil over high heat and simmer for 3 to 5 minutes to blend flavors.

Spray a 5-quart slow cooker with nonstick cooking spray. In a separate bowl, combine ricotta cheese, egg, and 1/2 cup mozzarella cheese. Spoon 1/3 of tomato mixture into slow cooker and top with half of frozen pierogies. Spread one half of ricotta mixture over pierogies and repeat above steps with half of tomato mixture, remaining pierogies and remaining ricotta mixture. Top with remaining tomato mixture and remaining mozzarella cheese.

Cover slow cooker and cook on High for 2 to 2 1/2 hours or on Low for 4 hours. Do not stir.