Place the smaller rectangles of dough on the baking sheet. Spread half the filling, leaving 2.5-cm (1-inch) border on each side. Add the tenderloins and the remaining filling. Brush the sides of the dough with the beaten egg. Top with the remaining dough rectangle, pressing down the sides to seal in the filling. Trim the excess, as needed. With a knife, make a few incisions in the centre of the dough. Brush with the beaten egg. Refrigerate for 30 minutes.