Clean the mushrooms and cut them into thin slices.
In a pan, heat two spoons of oil and a garlic clove. Add the mushrooms and let them cook for a few minutes, until when they are softer and their water dissipates. Then, let them cool.
In a bowl, mix eggs, ricotta cheese, parmesan, gruyère cubes and frankfurter rounds. Carefully stir and add the mushrooms.
Preheat the oven at 180°C, cover a sheet pan with parchment paper and put puff pastry on it, piercing the bottom with the prongs of a fork. Pour the mixture at the centre of the pastry, leaving the edges free, since you must fold them inwards.
Bake for 35-40 minutes.
Remove the savoury pie from the oven and let it cool slightly before serving.