Grease and flour a 7in cake tin.  Cut a baking paper disk to cover base of the tin and grease.

Set the oven to 175ºC/350ºF.

Add butter to a stand mixer and with the paddle attachment soften and cream the butter.

Add the castor sugar a tablespoon at a time beating thoroughly until the mixture is soft and light.

Add the eggs one at a time, adding one third of the almond flour with each egg.  Beat well.

Fold in the flour and almond essence with a metal spoon and pour cake mixture into the prepared tin.

Bake for 45 minutes or until cooked.  The cake will shrink very slightly from the side of the tin.

Turn out onto a cake rack and allow to cool completely before sprinkling with castor sugar.