In a bowl, mix the whole egg with the powdered sugar. Add pistachio powder (I mixed 23g pistachios), flour and melted butter. Mix well.
In a separate bowl, whisk the egg whites with the powdered sugar. Gently fold into the mixture using a pastry blender. Pour the cookie dough onto a baking tray lined with baking paper. Bake at 180°C. Remove the cookie from the oven when it has a nice golden color, and let it cool before peeling it from the paper and cutting out the cookie with a cookie cutter. You’ll have some cookie left over.
Place the gelatine sheet in a large bowl of cold water. In a saucepan, heat the 60g liquid cream with the pistachio praline. Melt the white chocolate in the microwave and add the hot cream on top. Add the wrung-out gelatine. Mix well. Top up with 120g cold cream. Mix again. Set aside in a bowl, filter on contact and chill for at least 4 hours.
In a bowl of cold water, place the gelatine leaves. In a small saucepan, heat the 00g liquid cream with the pistachio praline. Remove from heat and add the gelatine and melted white chocolate. Mix and set aside. Whip the cold cream with an electric mixer. Pour over the previous mixture and stir gently. Pour into your silikomart insert mould and place in the freezer.
Soften the gelatine sheet in a bowl of cold water. In a bowl, mix the egg yolk with the powdered sugar. Heat the milk in a saucepan. Remove from heat and pour over egg yolk mixture, stirring constantly. Return the mixture to the saucepan and cook over low heat until it reaches 82ºC. Remove from the heat and stir in the gelatine. Pour this hot custard over the chocolate, stirring with a whisk until melted. Set aside. Whip the chilled cream with an electric mixer and add to the custard in two or three batches, mixing gently with a spatula each time. Pour over the crunchy pistachio praline and place in the freezer. 5 minutes. Then place the second pistachio cookie and return to the freezer.
Assembly
Fill your silikomart cylinder mould halfway with chocolate mousse. Add the frozen pistachio insert. Top with a little chocolate mousse and finish with the pistachio cookie. Place in the freezer overnight or for at least 6 hours.
The next day, unmold your entremets and place them on a wire rack. Apply the rocher glaze.
Melt milk chocolate and neutral oil. Mix well. Add chopped almonds. Mix again. Frost the cakes. You can collect any excess icing that has dripped under your rack for reuse.
Using an electric mixer, whip up the pistachio ganache. Fill a pastry bag fitted with a fluted tip and poach the ganache onto your entremet, then use a plain tip and poach this one too.
I decorated with a few gold leaves and pistachios.