Heat oven to 180`c and grease and line a 22cm spring form cake tin with soft butter and line the bottom with baking parchment. Shake a little flour around the buttered edges. Melt the chocolate, butter, coffee powder and chilli. Whisk the egg yolks with the brown sugar and caster sugar, either in an electric mixer or with an electric hand whisk, for 5-10 minutes until thick and pale. In a separate bowl, whisk the egg whites until soft rounded peaks form. Pour the chocolate mixture onto the beaten yolks and sugar, and gently mix until smooth. Add the almonds and flour and mix again. Spoon the egg whites into the chocolate mixture and gently fold together. Finally, fold in the broken walnuts. Gently pour the batter into the prepared tin and bake for 40-45 minutes until the cake is set but with a slight jiggle in the centre. (If the cake is starting to brown too quickly, cover with a piece of baking parchment.) Leave to cool in the tin – it will sink a little as it cools. Run a knife around the inside of the cake tin to loosen. Remove the baking parchment and place on a cake stand. In a saucepan, heat together the coffee and coffee liqueur and allow to cool. Whisk the cream until soft peaks, then fold in the coffee and liqueur mixture. Spoon the cream on top of the cake and dust with a little cocoa powder and chocolate curls.