Makes either one thick single chocolate cake or, if you double it, a mighty layer cake. I've used a combination of buckwheat and rice flour here, though you can replace the buckwheat with other flours like chestnut, brown rice or amaranth. The bicarb will start to puff the mixture up soon after mixing so to keep the texture light and aerated don't spend too long folding it in.
230g drained tinned pears
125g dark muscovado or brown sugar
75g unsalted butter, melted
2 eggs (60g each)
2 tsp vanilla extract
2 tsp cider vinegar
50g buckwheat flour
50g white rice flour
1 tsp baking soda
For the icing
40g boiling water
40g unsalted butter, softened
about 250g icing sugar
1. Line a deep 20cm round springform cake tin with non-stick paper, and heat the oven to 180C conventional (160C fan forced).
2. Put the drained pears in the blender until very smooth then tip into a mixing bowl. Stir in the sugar until it dissolves, then mix in the butter until smooth.
3. Beat in the eggs, vanilla and vinegar, then stir in the cocoa until smooth.
4. In a small bowl mix together the buckwheat and rice flours with the baking soda, then add this to the chocolate mixture and fold in quickly and evenly.
5. Tip the mixture into the tin, smooth the top and bake for 35 minutes or until a skewer poked in comes out clean. Leave the cake to cool in the tin.
To make the icing
1. Put the cocoa in a bowl, pour on the boiling water and beat until smooth.
2. Add the butter, cut into thin slices if it's cold, then stir till it melts through.
3. Beat in the icing sugar, more or less depending on how thick you want it.
Tip: While the cake is warm cover the top with a plate, plastic wrap or bag (avoid pressing down on the cake); this stops it drying out as it cools.