Preheat the oven to 425 deg F, and line two baking sheets with parchment. *Mary's recipe just says grease two baking sheets - I find parchment safer and more effective.
Measure the flour, baking powder, and salt into a large bowl. Add the butter and rub it in with your fingertips until the mixture resembles fine breadcrumbs. Stir in the sugar.
Beat the eggs in a large liquid measuring cup. Then add milk until you have a total of 300mL. Place about 2 tbsp of the mixture aside for glazing the scones later.
Gradually add the egg mixture to the dry ingredients, stirring gently just until you have a soft dough. The mixture will be on the wet side, sticking to your fingers. *Do not be tempted to overwork your dough, it will make your scones dense.
Turn the dough onto a lightly floured surface, and flatten gently with your hands (or a rolling pin) to a thickness of 1/2-3/4in (1.25-2cm). Using a 2inch (5cm) cookie or biscuit cutter, cut out your scones. *Dipping your cutter in flour first will allow you to cut more effectively. Careful not to twist or turn your cutter on the way down. Push straight down so your scones will rise evenly. Re-roll your dough and cut as needed.
Arrange the scones on the prepared baking sheets, and brush the tops with the reserved egg mixture. Bake 10-15 min, until well risen and golden. Transfer to a wire rack to cool, covered with a tea towel to keep them moist.