Heat oven to 180`c. Grease 6 small individual cake tins with soft butter and line the bottom with baking parchment. Shake a little cocoa powder around the buttered edges. Melt the chocolate and butter together over a pan of simmering water. Once melted, whisk together until smooth and add the espresso powder and chilli powder. 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, using a clean whisk, beat the egg whites and cream of tartar 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. Pour the batter into the prepared tins and bake for 20 minutes until the cake is set but with a slight jiggle in the centre. Allow to cool before removing out of the tins. Serve with a scoop of praline ice-cream.