Genoese Sponge

Ingredients

• 200 g sugar
• 150 g butter
• 170 g potato flour (starch)
• 110 g wheat flour
• 12 egg yolks
• 7 egg whites
• lemon zest

Instructions

1. Work the yolks with butter and sugar, add the flours, and work half an hour.
2. Fold in whipped whites and bake thin in a prepared tray.
3. Cut into diamonds and dust with icing sugar.