Taken from A Table for Friends
by Skye McAlpine, published by Bloomsbury.
1. Heat the oven to 180 ̊C/Fan or 160 ̊C/Gas 4. Butter a 20cm round cake tin and line with baking parchment.
2. Pour the chestnut purée into a large mixing bowl. Separate the eggs and lightly beat the yolks with a fork, then add them to the purée. Pour in the ground almonds, add the cocoa and mix well.
Roughly chop the rosemary leaves and add them to the batter, then stir until well combined.
3. In a second bowl, whisk the egg whites until stiff, then fold into the chocolate mix. Pour into the tin and sprinkle on a few rosemary sprigs. Bake for 40–45 minutes until a skewer comes out clean. Leave to cool in the tin, then turn out. The cake will keep nicely for 2–3 days.
4. Dust with icing sugar before serving.