Chopped onion and fry in olive oil until golden on a slow fire. Add tuna, cooked and chopped eggs and tomato paste. Fry a little, about 1-2 minutes. with stirring and removing from the heat. Forge mixture with salt and pepper. In tray covered with baking paper and oiled, insert the first sheet of puff dough. With a fork jab here and there the bottom of the base, so as not to inflate. Pour and spread the mixture well, leaving one finger covered the edges of the base. Cover with second base and seal the edges using a fork, fingers, etc. Spread some of the beaten yolk, in which a tiny dribble of milk (1 tsp) of 200C and bake in preheated oven for about 20 minutes, until browned.