Pre-heat the oven to 180?c and butter and base line two 20cm in cake tins.
Place the beer and 125g of the muscovado sugar in a pan and slowly bring to the boil. Remove from the heat and stir in the bicarbonate of soda. Leave to cool for about 1 hour. Sift the flour and ginger into a bowl. Whish together the eggs, the remaining muscovado sugar, caster sugar, oil, then add slowly to the flour, stirring. Add the beer mixture and fold together gently. Tip into the prepared tins and bake for 25 minutes until just firm to the touch. Cool in tins for 30 minutes then transfer to a wire rack to cool, peeing off the paper when cold.
The rhubarb fool
Place the rhubarb in a pan with the elderflower syrup and sugar and bring slowly to the boil, stirring continuously. Cook gently for 8 – 10 minutes until just tender. Allow to cool. Put the cream in a bowl, then gradually fold in the cooled rhubarb.
To serve, place one cake on a large serving plate and spread the fool generously over. Place the other cake on top and top with more fool so that it slithers down the sides of the cake and look altogether too tempting for words!!