Instructions

1. Preheat the oven to 180°C.
2. Separate the eggs into two mixing bowls.
3. Mix the egg yolks with sugar, then add the Prosecco, lemon zest, lemon juice and vanilla essence. Add the flour and baking powder, gently stir through.
4. In another bowl, using an electric whisk, beat the egg whites until stiff. Add a spoonful to the champagne mixture, stir, then fold in the rest.
5. Grease and line a cake tin, then fold in the batter. Even the top.
6. Bake at 180°C for 25 minutes, then reduce the temperature to 150°C and bake for a further 20 minutes until golden.
7. Turn off the oven, open its door and leave the cake to cool gradually - this way it shouldn't collapse.
8. Sprinkle with icing sugar before serving.