In a large bowl mix together the ricotta cheese, spinach, 1½ cups mozzarella cheese and egg. Spoon the cheese mixture into your shells.
Spread a layer of sauce on the bottom of the slow cooker and place stuffed shells on top. It's okay to stack the shells.
Pour layer the cooked ground meat over the shells, then spread the remaining sauce on top. Cover and cook on low for 3 - 4 hours, until bubbly and heated though.
About 30 minutes before you're ready to eat, top with the remaining shredded mozzarella. Cover and continue cooking until cheese is melted.
Serve with Italian parsley and parmesan cheese.
Notes
Calories are automatically generated. For best results calculate based on your exact ingredients.