Preheat oven to 180°C.
Make the sauce by frying garlic and onion in olive oil, then adding cherry tomatoes, crushed tomatoes, and dried Italian herbs. If needed, you can top up with passata or pasta sauce.
Make the filling by combining thawed spinach, ricotta cheese, basil, parmesan cheese, shredded cheese, salt, and pepper in a bowl.
Cover a large tray with a layer of pasta sauce.
Stuff the pasta shells with the filling and place them in the tray.
Cover the shells with remaining sauce.
Bake for 20 minutes or until pasta is cooked.
Top with shredded cheese and bake until melted.
Serve with fresh basil and salad.