Preheat oven to 180ºC/350ºF.
Grease and line 3 20cm round cake tins.
Cream the butter and 1 Cup of the sugar together until light and fluffy.
Add the egg yolks, vanilla, lemon juice, greek yoghurt, lemon zest and lemon curd and continue mixing.
Then, add the flour, baking powder and salt and mix well.
Meanwhile, in a separate bowl, whip the egg whites and the remaining sugar until stiff peaks.
Fold the egg white into the batter.
Divide the batter between 3 pans and bake for 25min or until golden brown.
Allow to cool slightly, then remove from cake tins and transfer to wire rack to cool further.