Preheat the oven to 170 oC and grease a 8" cake tin

Place 180g of the caster sugar, ground cinnamon, orange zest, lemon zest and 6 egg yolks into a large bowl

Beat until light and fluffy

Stir in the ground almonds

In a clean bowl place the egg whites and beat until stiff

Beat in the remaining caster sugar

Gently fold into the ground almond mixture

Pour into the cake tin and bake for 30 minutes

Remove from the oven and allow to cool completely

Dust the top with icing sugar, you can use a stencil to get the traditional St James Cross shape on top of the cake