with a fork.
Stuff with the tuna and onion mixture and distribute it evenly, leaving about 2 cm free between the filling and the edges, and add the grated provolone on top.
Cover with the second rectangle of puff pastry. Prick the surface and seal the edges by folding them inward and pressing with the prongs of a fork.
Beat the egg with the milk in a small bowl and brush the entire surface of the rustic pastry.
Cook in a preheated static oven at 395°F/200°C for
