Preheat your oven to 180°C (350°F) to get it ready for baking the shells.
Bring a large pot of salted water to a boil and cook the pasta shells for about 8 minutes until just al dente. They should be tender but still hold their shape.
Drain the shells carefully and set them aside to cool slightly so you can handle them without burning your fingers.
In a mixing bowl, combine ricotta, shredded mozzarella, chopped spinach, and a pinch of nutmeg. Mix until well blended and the spinach is evenly distributed.
Use a spoon or piping bag to stuff each shell generously with the cheese mixture, pressing lightly to seal the filling inside.
Spread a thin layer of marinara sauce in the bottom of a baking dish, then arrange the stuffed shells on top. Cover with remaining marinara and sprinkle extra shredded cheese evenly over the shells.
Bake uncovered in the preheated oven for 25 to 30 minutes, until the sauce is bubbling and the cheese on top is melted and golden brown.
Remove from oven and let rest for 5 minutes to allow the cheese to set, making it easier to serve and preventing messy bites.
Serve hot, with some extra sauce if desired, and enjoy the gooey, cheesy, spooky goodness!
