Preheat the oven to 180C/350F/gas mark 4
Use two 20cm/8 inch sandwich tins.
Grease and line the sandwich tins. Sift together the flour and carob. Cream the butter and sugar until light and fluffy. Stir in the buttermilk. Fold in the flour and carob.
Turn the mixture into the prepared tins and bake for about 40 minutes. Remove from the oven and allow to cool in the tins for 5 minutes. Turn out on to a wire rack and leave to cool. When cold, split each cake into two layers.
Icing: Cream the butter with the orange rind until soft. Gradually beat in the icing sugar, alternately with the orange juice. Use some of the butter icing to sandwich the cakes together. Spread the remaining butter icing over the top and sides of the cake. Decorate the top of the cake with the orange segments.
