Preheat the oven to 220C. Sift the flour and the baking powder into a bowl in order to allow air into the mixture. This is an important step.
Rub in the butter until a breadcrumb like consistency is achieved. Cold, dry hands make this step easier.
Grate the cheese. Stir most into the flour mixture but keep a little back for sprinkling on top of the scones.
Crack the egg into a measuring jug and whisk lightly. Top the beaten egg up with milk until the mixture reaches the half-pint or 285ml mark. Whisk again to combine.
Make a well in the centre of the dry ingredients and pour the majority of the egg mixture into the bowl, keeping back a little to brush the scones with before baking.
Stir the mixture to combine and then knead very briefly, just enough to bring it together. Be careful not to overwork the dough.
Roll out the dough quite thickly (1 1/2 inches) and cut out circles with a scone cutter or a glass. Don't twist as you cut or the scones will rise unevenly. Alternatively, you can cut the dough into traditional wedges.
Place the scones on a baking tray. Glaze the tops with the egg and milk mixture then sprinkle a little cheese over each one.
Put straight into the very hot oven and bake for around 13 minutes or until well risen and browned. Afterwards, cool on a rack for five minutes before eating warm with butter.