Gâteau de Savoie

Method

Preheat the oven to 180C and lightly butter a 23cm round cake tin, dusting with flour. Whisk the egg yolks with 120g caster sugar until pale and thick, then add vanilla extract. Sift together the potato starch, plain flour and salt, then gently fold into the yolk mixture. In a separate bowl, whisk the egg whites with the remaining 30g caster sugar until stiff peaks form. Carefully fold the meringue into the batter in three additions, being gentle to preserve the air. Pour into the prepared tin and bake for 35-40 minutes until golden and a skewer comes out clean. Cool in the tin for 10 minutes before turning out onto a wire rack, then dust generously with icing sugar.