Oven temperature 175° C (350° F)
Preparation time: 10 minutes
Baking time: Under an hour

This is a recipe typical of the Savoy region.

1. Whisk together the egg yolks and sugar until light; mix in the whole egg and then add the flour and potato starch;
2. beat the 2 egg whites with 35 g of sugar until stiff peaks form; gently fold the beaten whites into the egg yolk mixture, lifting the batter to incorporate air.
3. Butter and flour a sponge cake pan, or failing that, a loaf tin; pour the mixture into the prepared pan (it should come up no more than 2/3 of the pan’s height); bake in a 175° C (350° F) oven until done – check with a skewer or thin knife blade.
4. Serve warm with crème anglaise, fruit in syrup or simply vanilla ice cream.