Preheat the oven to 220°C/200°C Fan/gas mark 7/425ºF, and straightaway put your pan into the oven to heat up while you prepare the batter.
Beat the eggs with the caster sugar in an electric mixer until light and frothy. Whisk in the milk, flour, vanilla, salt and grated nutmeg, and beat until you have a smooth but thin batter.
Wearing a thick oven mitt, remove the pan from the oven and put the butter carefully into the hot pan or tin and swirl it to melt, then quickly pour in the batter and return it to the oven.
Bake until puffed and golden brown, about 18–20 minutes.
Serve dusted with icing sugar, and a tumble of berries, if the idea appeals; otherwise, see Intro.
