50²µ/1¾´Ç³ú plain flour
45²µ/1½´Ç³ú caster sugar, plus extra for dusting
icing sugar, to decorate
pinch salt
2 tsp vanilla extract
knob melted butter, for greasing
4 large free-range eggs, separated
300ml/10fl oz full-fat milk
vanilla ice cream, to serve (optional)