This is a perfect Valentine's Day cake, as one would have to be in love to want to make this. Me? I'm just crazy. This is not for the faint of heart - it is both expensive to make and extremely labour intensive. The results are worth it though; the chestnut cream gives it a unique twist and it is so chocolate-y I think it's fulfilled my cravings for the next several months.
Base Brownie Layer:
1 oz bittersweet chocolate, chopped
4 tbsp/2 oz butter
1 egg2 tbsp sugar
2 tbsp brown sugar
1/4 cup flour
1/3 cup chopped roast chestnuts
Score the chestnuts and roast in a 400F/200C oven for 30 minutes, then peel and chop. Melt the chocolate in a bain marie then remove from the heat. Add the butter and whisk until smooth, then whisk in the egg and both sugars. Stir in the flour, followed by the chestnuts. Bake in a 6" greased springform pan or cake ring for 15 minutes in a 350F/180C oven. I used a strip of folded foil around the base to help seal the ring and prevent the edges of the brownie from baking faster than the middle. When the middle springs back when touched, remove & cool on a wire rack.
Centre Chestnut Cream Layer:
1 tsp powdered gelatin
1 tbps water
4 egg yolks
1/4 cup sugar
1 cup heavy cream
1/4 cup chestnut puree
In a cup or small bowl, sprinkle the gelatin powder over the water and let it absorb for 5 minutes. In a bowl, whisk the yolks and sugar together until it turns a pale yellow. Bring the cream to a boil, and whisk in the yolk mixture. Add the soaked gelatin, stirring over a low heat until the mixture thickens (around 10 minutes). Whisk in the chestnut puree. Pour through a sieve and refridgerate until partially
set. With the Brownie Base still in the pan, pour over the Chestnut Cream. Freeze for 2 hours.
Top Chocolate Mousse Layer:
3 tbsp sugar
2 tbsp water
3 egg yolks
4 oz bittersweet chocolate, melted & cooled to tepid
3/4 cup heavy cream
Bring the sugar and water to a full boil. Beat the yolks with an electric mixer, and pour over the hot syrup. Keep beating to prevent the eggs from cooking, and continue until the mixture is cool and has doubled in volume. In a separate bowl whip the cream to soft peaks, then take 1/3 of the whipped cream and whisk it into the tepid chocolate. Make sure the chocolate has not fully cooled! I was distracted by dinner while making this layer, and the cooled chocolate ended up not fully mixing into the mousse. Fold the yolk mixture into the cream/chocolate, then fold in the remaining whipped cream. Spread the mousse over the Chestnut Layer and freeze for 4 hours.
Chocolate Icing (optional):
1 1/2 tsp powdered gelatin
1 tbsp water1 cup sugar
3/4 cup cocoa
3/4 cup heavy cream
1/4 cup water
In a cup or small bowl, sprinkle the gelatin powder over the water and let it absorb for 5 minutes. Add the sugar, cocoa, cream, and water to a saucepan and bring to a boil stirring continually. Reduce the heat to med-low and cook for 5 minutes. Remove from the heat and add the soaked gelatin; to ensure this dissolves properly I found it easiest to add the hot chocolate mixture to the gelatin bowl bit by bit and then added it to the pan. Let stand until the icing is tepid but still fluid.
Place the cake on a wire rack and remove the ring/remove from the pan. I used a hot knife (ice cream cake-style) to get it out of the ring, then used my hands dipped in hot water to smooth the sides. Because the icing is similar to a ganache, you need to make sure the cake has a smooth base for it. If you decide not to ice the cake
(it's really not needed, as the cake is chocolate-y enough), sprinking cocoa on top and decorating would look good as well. This can be frozen for up to 3 days, and defrosted for 8 hours in the fridge prior to serving.
P.S. Make sure you keep all those egg whites!