Preheat the oven to 180 C. Clean the lemons under warm running water and grate the zest. Add all ingredients except the almond shavings and the icing sugar in a bowl and whisk until a smooth thick batter.
Pour the batter into the caketin (it will be half full) and smooth with a wet spatula and sprinkle the almonds on top. Bake the cake in the oven for about 45-50 minutes until golden and done.