Flour two baking trays. Whisk together the yeast, sugar and half the milk in a jug. Leave in a warm place until frothy, about 10 minutes.

Mix the egg with the remaining milk and the butter. Sift the flour and salt into a bowl. Add the yeast and egg mixtures and mix to a soft dough. Turn on to a lightly floured surface and knead until smooth and elastic, about 10 minutes.

Place in an oiled bowl, cover with cling film and leave to rise in a warm place until doubled in size, about 1 1/2 hours.

Turn out the dough on a lightly floured surface and knead for 2 minutes. Roll and stamp out 10 rounds with a 7.5 cm (3 in) plain cutter, re-rolling as necessary. Place on the floured trays, cover with cling film and leave to prove for 30 minutes.

Lightly grease a griddle or heavy frying pan. Cook the muffins a few at a time over a moderate heat for 5-8 minutes each side, until well risen. Leave to cool on a wire rack. Serve split and toasted with butter.