Spread a sheet of puff pastry on a baking sheet covered with baking paper or a silpat or similar.
In a frying pan slowly fry the onion cut in julienne and the red pepper chopped.
When they are fried, drain and spread on the puff pastry leaving about two centimeters of dough without covering all the way around.
Then put the bonito, previously drained of the oil and crumbled.
Cover with the other layer of puff pastry, to which we will cut two centimeters around to make it smaller.
Fold the bottom edge over this layer to close the pie.
Make a hole in the center and decorate with the remains of the puff pastry.
Paint with beaten egg and bake, following the instructions of the manufacturer of the mass until it is done.