Sift the flour into a bowl.
Using an electric hand mixer, cream together the butter and sugar until light and fluffy, 2 minutes.
Mix in the coffee essence/extract.
Now beat in the eggs into the creamed mixture, one at a time, adding a spoonful of flour with each egg which will prevent curdling.
Then fold in the remaining flour and chopped nuts.
Divide the mixture evenly between the prepared cake pans.
Bake for 30–35 minutes, until the tops of the cakes are firm and spring back when gently pressed with the tip of a finger.
Remove from the oven and place the pans on cooling racks for 2 minutes before turning out the sponges and removing the liners. Leave on the cooling racks to cool completely.
Meanwhile, to make the icing, sift the icing/powdered sugar into a large bowl and add the butter and coffee essence/extract. Beat together until the icing is smooth.
Once the sponges are cool, invert one of the sponges and place on a serving plate.
Spread with one third of the icing.
Then sandwich together with the other sponge.
Use the remaining icing to cover the top and sides of the cake.
Finally decorate the top with the walnut halves.