Once the manicotti is tender, sprinkle the shredded mozzarella cheese evenly over the top. Cover again and cook on LOW for another 15–20 minutes, just until the cheese is melted and bubbly.
Turn the slow cooker to WARM and let the bake rest for about 10 minutes before serving. This helps it set up a bit so it scoops more neatly. Serve straight from the slow cooker, making sure each portion gets some pasta, meat, sauce, and a good blanket of melted cheese.
You can swap the ground beef for Italian sausage, ground turkey, or a mix of whatever you have on hand; just brown and drain it the same way. If you’d like a bit more creaminess without adding extra ingredients, use a pasta sauce that already includes cheese or a creamy tomato base. For a meatless version, skip the beef and tuck a handful of frozen spinach or extra shredded mozzarella between the dry tubes before adding the sauce, understanding it won’t be as protein-heavy but will still be comforting. If your family likes a little heat, stir crushed red pepper into the sauce before pouring it over the manicotti. For smaller households, you can halve the recipe and use a smaller slow cooker, checking for doneness about 30 minutes earlier. Leftovers reheat nicely: add a spoonful of water or sauce, cover, and warm in the oven or microwave so the pasta doesn’t dry out. If your slow cooker runs hot, start checking the pasta at the 3 1/2 to 4 hour mark to avoid overcooking.
