This a fabulous cake for entertaining - rick and luscious but also gluten free. The addition of a little chestnut flour helps stabilise the mix and gives it a bit of extra flavour. However chestnut flour is hard to find, although at the right time of year you can buy it online in Australia from http://cheznuts.com.au/store/. You can leave the chestnut flour out or replace with another flour if you can't find it.
200 gms 70% chocolate
200 gms cultured unsalted butter
200 gms chestnut puree (available in cans).If sweetened leave out sugar from mix
50 gms chestnut flour
3 eggs (approx 92 gms egg whites, if your eggs are small you may need four)
110 gms caster sugar
• Line the base of a 20 cm tin with baking paper. Do this by smoothing the baking paper over the base and tucking it through the edge, then pull it tight. Trim off the edges.
• Butter the sides of the tin.
• In a large steel bowl over a pan of simmering hot water, melt chocolate and butter together. Do not let the water reach the underneath of the bowl.
• In a separate pan warm the milk , chestnut puree and chestnut flour together and mix until smooth. The puree I use is very stiff. If it is not stiff, use less milk.
• Take the chestnut mixture off the heat when it is mixed together. Beat the egg yolks and beat into the mixture. If the chestnut puree is unsweetened add the sugar at this point, otherwise leave out.
• When the chocolate mix is melted take the chocolate mixture off the heat.
• Beat the eggwhites until they form stiff peaks. Egg whites beat better in a copper bowl, if you happen to have one. (You can clean them using lemon juice.)
• Mix the chestnut and chocolate mixture together, then fold in the beaten egg white
• Pour the mix into the cake tin.
• Bake at 150 C ( fan) for 45 – 50 minutes until a skewer is clean when you insert it into the cake and pull it out. Allow to cool on a rack, then remove from the tin.
• Decorate with poached pears, or strawberries and/or raspberries, and sprinkle with sieved icing sugar or chocolate curls