- Preheat oven to 160 C.
- Lightly grease and line a 20cm round cake pan.
- Beat the butter, rind and sugar, until light and fluffy. Slowly ad the egg yolks, beating well.
- Stir in the juice, ground almonds and polenta.
- Whip the egg whites, until soft peaks form. Carefully fold into the polenta mixture.
- Spread the mixture into the prepared pan. Bake for about 1 hour or until a skewer inserted in the centre comes out clean.
- Meanwhile, boil the lemon juice and sugar, stirring until the sugar is dissolved. Spoon evenly over the hot cake.