Prepare the craquelin (this can be done the day before). In a bowl, mix the softened butter, flour, and sugar. Spread the mixture between two sheets of parchment paper and roll it out with a rolling pin. Use a round cookie cutter the size of your future choux (large and small) to mark circles in the dough. Place the parchment paper back on top and freeze for at least two hours.

Preheat the oven to 350°F (180°C). To make the choux pastry: In a saucepan over medium heat, combine the water, butter, sugar, and salt. As soon as it comes to a boil, remove from heat and add the flour all at once. Mix well, then cook the dough over low heat for 2 minutes, stirring constantly to dry it out. Remove from heat and let cool.

Bake at 350°F (180°C) without opening the oven door for 20 to 30 minutes. The choux are done when they are puffed and golden. Prepare the chocolate pastry cream.

To make the pastry cream: Grate the chocolate. Pour the milk into a saucepan and heat it. In a mixing bowl, whisk the egg yolks with the sugar until the mixture is pale, then add the cornstarch. Gradually whisk in the hot milk, then return everything to the saucepan and cook over low heat, stirring constantly, until thickened.

When the cream is almost done, add the grated chocolate and mix well until fully melted.

Pour the pastry cream into a bowl, cover with plastic wrap, let cool, then refrigerate for at least 1 hour before using.

Prepare a vanilla whipped cream. In a stand mixer bowl, beat the heavy cream with vanilla seeds until it starts to thicken, then add powdered sugar near the end. The whipped cream should be very firm.

To assemble: Fill the choux with pastry cream. Stack the small choux on top of the large one, using a little whipped cream to stick them together. Pipe small dollops of whipped cream around the seam and on top. Decorate with chocolate as desired. Enjoy!