In a bowl, mix the powders together: 65g flour, 65g caster sugar and a little vanilla powder. Add 1 egg, liquid vanilla and 20g melted butter. Mix well. Beat the two egg whites with an electric mixer.
Take a small portion of the egg whites and mix with the powders to loosen the mixture. Add the remaining egg whites, stirring gently with a spatula.
Pour the dough onto a baking tray lined with baking paper. Smooth with an angled spatula to ensure an even layer. Crumble in pieces of marrons glacés.
Bake in the oven at 170°C for 15-16 minutes.
Leave to cool, then cut out your biscuit using a circular biscuit cutter slightly smaller in diameter than your tin.
Place the biscuit at the bottom of your frame.
Brown mousse 50g single cream 180g chestnut cream 100g single cream 3.5g gelatine
Add the gelatine leaves to a large bowl of cold water. Heat 50g of single cream in a saucepan. Remove from the heat and add the softened gelatine.
Pour over the chestnut cream. Mix well. Set aside. Whip the remaining 100g of cold single cream with an electric mixer. Gently fold into the previous mixture when the temperature is below 30°C.
Assembly
Pour the brown mousse into the silikomart half sphere mould, leaving a little room for the biscuit. Finish with the biscuit. Place in the freezer overnight or for at least 6 hours.
The next day, unmould the frozen entremets and immediately apply the white velvet spray.
I decorated them by placing a marron glacé on top and a small leaf of edible gold.