Start by making the béchamel. Melt the butter in a saucepan on medium heat. When melted, spoon in the flour and whisk for a few minutes until golden and toasted.

Pour in the cold milk in a thin stream, stirring constantly to avoid lumps.

Cook on medium-low heat until thickened and season with a good pinch of salt and grated nutmeg as to give the béchamel a delicate spiced smell.

Transfer the béchamel sauce into a bowl and let it cool.

When the béchamel has cooled down a bit, add the mozzarella cut into small pieces and a sprinkling of black pepper.

Cut the tomatoes into fillets, drain them and put them aside.

Now prepare the rustici. Heat the oven to 200°C (390°F) and line a baking sheet with parchment paper.

Roll out the dough and cut out 18 discs 10 cm (about 4 inches) wide. There will be leftover puff pastry dough, cut smaller discs from there.

Place a third of the discs on the baking sheet and brush them with a beaten egg.

Place another disc on top of them - you’ll have a more resistant bottom -, then brush the edges with the beaten egg.

Cover the filling with the last disc, pressing your fingers all the way around to seal the edges. Press a smaller cookie cutter, as large as the filling, onto the rustico, to give it its traditional shape.

Brush the rustici with the beaten egg.

Bake the rustici for about 20 minutes, or until they are well puffed up and golden.

You can eat them immediately, or wait and have them warm. They can be kept in the fridge for 1-2 days, just heat them in the oven or in a non-stick pan before eating them.