In a large mixing bowl, combine 2 cups of flour, 1 packet of instant yeast, and 1 teaspoon of salt. Gradually add 1 tablespoon of olive oil and 1 cup of warm water, stirring until a shaggy dough forms.

Knead the mixture on a floured surface for about 8 minutes until the dough is smooth and elastic, then set aside.

Place the kneaded dough in a lightly oiled bowl, cover it with a damp cloth, and let it rise in a warm spot for about 1 hour.

Preheat your oven to 220°C (430°F). Lightly flour a clean surface to roll out your calzones.

After the dough has risen, punch it down gently and divide it into small balls, about the size of a baseball. Roll each ball out into a 6-inch round circle.

Cut each circle into a bat shape using a sharp knife, making sure to include wings and ears.

On one half of each bat-shaped dough piece, layer your chosen fillings, ensuring to leave a border around the edges.

Carefully fold the other half of the bat dough over the filled portion and gently pinch the edges to seal.

Lightly apply an egg wash made from one beaten egg over each calzone.

Transfer your bat-shaped calzones to the preheated oven and bake for 15 to 20 minutes.

Once baked, remove the calzones from the oven and allow them to cool for a few minutes before serving.