Put the olive oil in a casserole. Cook the onion and the garlic until are translucent. Add the parsley, cook until looks bright green. Add the tomatoes stir and add the salt. Cook until is dry. Add the tuna, stir and taste, put more salt if needed.
Flatten 1/2 of the puff pastry on a floured board, fill a 12 inch diameter glass pie pan.
Put in the tuna mix into the glass pie pan. Cover with the sour cream and the cheese.
Flatten the other half of the puff pastry, place pastry over top of tuna pie and tuck in the sides. With a fork make some holes. Glaze with the beaten egg.
Bake for 20 minute or until pastry has risen and is golden and crispy.