Bring a large pot of salted water to a boil and add your pasta. Cook until just al dente, about 2 minutes less than package directions. Drain and set aside.

In a medium saucepan over medium heat, melt butter. Whisk in flour to create a roux, cooking for 2 minutes. Gradually whisk in milk until thickened, 3-5 minutes. Remove from heat, stir in cheddar and parmesan until creamy.

Fold the cooked pasta into the warmed cheese sauce, ensuring every piece is coated. Allow to rest for a moment.

Preheat your oven to 375°F (190°C) and butter a large casserole dish. Spoon the cheesy pasta mixture into the dish, spreading evenly.

Cut mozzarella into ghost shapes and place atop the pasta. Add sesame seeds for ghost eyes.

Bake for 20-25 minutes, or until the cheese is bubbling and golden brown.

Remove from oven and let sit for a few minutes before serving. Enjoy your spooky dish!