Pre-heat the oven to 160C (350F) and grease and line a square 20cm (8") cake tin.

In the bowl of an electric mixer, beat the butter and sugar together until light and fluffy.

Add the eggs, one at a time, mixing after each addition.

Sift the flour, bicarb, salt and spice together and then add half to the batter and beat it through.

Add half the buttermilk and mix it in then repeat with the remaining flour and buttermilk.

Add the banana and hazelnut meal and mix them through then spread the batter into the tin.

Bake for 40-45 minutes or until a cake tester inserted in the middle comes out clean.

Leave to cool in the tin for 15 minutes then transfer to a wire rack to cool completely.

Meanwhile make the icing.

Beat the cream cheese in the bowl of an electric mixer until smooth then add the icing sugar and lemon juice.

Beat on low until incorporated and then increase the speed to high and beat until white and spreadable (add a little extra lemon juice or water if needed).

Spread the cooled cake with icing and top with hazelnuts then dust with icing sugar.