How to cook
Having fried mushrooms to soften them, add chopped tuna. After about a minute, flavor the mixture with salt and pepper, then leave to stew to full readiness.
Divide the puff pastry into three equal parts. The filling from the pan is split between them, alternating batter and filling. The penultimate stage is to cut the pie into several pieces.
Beat the eggs in a separate bowl and milk well, then pour the mixture on the cut pie. Bake in a moderately hot oven, at about 356°F (180 °C).