Boil a large pot of salted water, then add gho-gheroni and cook until al dente, about 6-8 minutes. Drain and set aside.

In a medium-sized saucepan, melt butter over medium heat. Whisk in flour, cooking for 2 minutes until it forms a roux. Gradually pour in milk while whisking continuously, until sauce thickens, about 5-7 minutes.

Once the sauce thickens, remove from heat and stir in cheddar and Parmesan cheeses until melted. Add salt and pepper to taste.

Fold cooked gho-gheroni into the cheese sauce until coated. Set aside for baking.

Preheat oven to 375°F (190°C). Scoop the mixture into a greased 3-quart casserole dish and level the top.

Slice mozzarella into ghost shapes and arrange them atop the pasta mixture, adding sesame seeds or peppercorns for eyes.

Bake for 20-25 minutes, or until bubbly and golden brown.

Remove from oven and let cool for a few minutes. Serve into bowls, ensuring each serving includes a mozzarella ghost.