This sponge cake richly filled with chestnut cream and chocolate glaze makes a superb party cake:
Difficulty:[usr 3]
Break the eggs into a terrine, add 1 pinch of salt and 125g of caster sugar. Place this terrine in a saucepan filled with water kept warm over low heat. Beat this mixture with a whisk until it triples in volume, but never let it boil. The dough should stay warm. Remove the terrine from the pot of water when the result is achieved.
Melt 60 g of butter in a small saucepan and let cool. Then pour 125 g of sifted flour on the surface of the dough, then mix gently with a wooden spatula. When part of the flour is incorporated, pour in the melted butter and finish mixing.
Butter and flour a 22 cm round or square mold, 6 cm deep. Pour in the batter and bake in the oven at 180°C for about 30 minutes, avoiding opening the door. Unmold the sponge cake when it comes out of the oven, turning it over on a wire rack. Cover it with a clean, dry towel. Wait until it has completely cooled before cutting it in half lengthwise with a serrated knife.
Meanwhile, mix the chestnut cream, the rest of the caster sugar and a tablespoon of rum. Whip the very cold fresh cream vigorously. When it is thickened, add it to the chestnut cream, then spread this preparation on the cut side of the two sponge cake layers.
Melt the chocolate broken into small pieces in a saucepan over very low heat with 1 tablespoon of water. Mix 1 glass of water and the granulated sugar and boil this mixture, then pour it over the melted chocolate. When this icing is homogeneous, replace the two sponge cake layers covered with chestnut cream (both sides against each other), then spread the chocolate icing on the top and sides with a metal spatula . Serve very cold.
You can decorate the top with candied chestnuts or serve with vanilla custard.
Source:Les Cuisines Régionales de France. Brittany. Editions du Fanal