Prepare the tin with a little melted butter and preheat the oven to 180℃ / 350℉.
Whisk the sugar and eggs until frothy.
100 g caster sugar (superfine sugar), 2 medium eggs
Lightly whisk in the rest of the ingredients.
100 g plain flour (all-purpose flour), 100 g butter, 0.75 tsp baking powder, 1 tsp vanilla extract, zest of a lemon
Leave to stand for 10 minutes. Then pour carefully into the tin.
Bake for 8-10 minutes until risen and firm in the middle.
Cool in the tin for a few minutes, then carefully remove from the tin.
Dust with icing sugar to serve.
Icing sugar