To make the dough, dissolve the fresh yeast, if using, in the milk. If using dried yeast, stir the caster sugar into 2/3 cup of the milk and whisk in the yeast. Cover the bowl and leave to stand in a warm place for 15 minutes, or until frothy, then stir in the remaining milk.
Sift the ﬂour, salt and sugar into a bowl and rub in the butter. Make a well in the centre, pour in the yeast liquid, add the beaten egg and mix to a soft dough. Knead the dough on a lightly ﬂoured surface for 5 minutes. Put into a bowl, cover and leave in a warm place for about an hour, or until doubled in size.
Divide the dough into 15 equal pieces, shape each piece into a smooth ball and place, spaced apart, on greased baking trays. Cover loosely with plastic wrap and allow to rise until doubled in size.
Preheat the oven to 220°C. Bake in the centre of the oven for 10–15 minutes, or until well risen, golden brown and hollow-sounding when tapped on the bottom. Cool on a wire rack, then sift lightly with the icing sugar. Serve split and filled with cream and jam or golden syrup.