Whisk egg and milk together. Add to dry ingredients and stir to combine with a butter knife to form a dough. You may need to add a little extra milk (up to ½ tablespoon) so that mixture forms a dough and holds together.
Flour your work bench and then break dough into two parts. Use a rolling pin to roll mixture out until it is approximately 3mm thick.
Cut out with an oval or circle-shaped cutter and place on a baking tray lined with baking paper.
Brush the biscuits with a little extra milk and then prick each biscuit with a fork.