125g Chelesa Caster Sugar
4 eggs, separated
1 orange, finely grated zest
125g butter, softened, but not melted
250g ground almonds
60g flour
Chelsea Icing Sugar, for dusting

Pre-heat the oven to 180C. Butter and flour a 22cm diameter cake tin.
Beat the sugar, egg yolks and zest until pale and thick.
Beat in the butter then stir in the almonds and flour until well mixed.
Beat the egg whites until they hold soft peaks.
Add a little of the whites to the almond mixture and beat it in to loosen the mixture.
Fold in the remaining beaten egg whites making sure there are no lumps.
Spoon into the tin and bake 20-25 minutes or until a skewer inserted into the middle comes out clean.
Remove from the oven, cool and dust with icing sugar.