Thousand-sheets

1 Roll out the first puff pastry to about 3 mm. Prick it with a fork. Place it between two baking sheets. Bake for 20 minutes thermostat at 180 ° C (thermostat 6). Perform the same operation for the other two doughs.
2 Prepare the pastry cream: split the vanilla pod in half. Bring the milk to the boil with the vanilla pod. Meanwhile, combine the egg yolks (keep the white of an egg for the icing), the sugar and the flour in a bowl. When the milk is boiling, immediately pour it into the bowl. Mix and return to cook in the pot for a few minutes so that the mixture thickens. Let the cream cool. When it is very cold, add the softened butter and the flavor of your choice, mix well. In a bowl of water, let the gelatin soften then melt for 20 seconds in the microwave and add to the custard. Put in the fridge.
3 Assembly: take a first sheet of puff pastry and spread the pastry cream evenly with a metal spatula. Position a second sheet of puff pastry on top and spread a second layer of pastry cream and finally place the last sheet of puff pastry.
To finish
Icing: Mix the icing sugar with the egg white until thick enough. Take two tablespoons of this frosting and add the coffee extract or liquid chicory to obtain a second dark brown frosting. Spread the white frosting evenly over the entire mille-feuille. Using baking paper, form a cone with a fairly small opening. Fill this cone with dark icing and make horizontal and parallel lines, 3 cm apart. With the tip of a knife, score the surface vertically to effect a marbling. Keep chilled until serving.