Preheat oven to 220c/430f
Add self-raising flour (3 cups/450 g) and chopped butter (100 g) to a medium-sized bowl. Using your fingertips, rub the butter into the flour (or you can use a pastry cutter like you see in the process photo in the body of this post) until the mixture resembles coarse breadcrumbs.
Add the grated cheddar cheese (2 cups/160 g) and salt (½ tsp) to the flour mixture and combine using a flat-bladed knife.
Then add buttermilk and mix to combine, again using a flat-bladed knife. For the final few strokes, I bring the dough together with my hands.
Turn the dough out onto a lightly floured bench/board and knead the dough very lightly (only a few turns) until just smooth, then pat the dough out into an even disc approximately 2½ cm/1" thick.
Dip a round 6cm/2½″ scone cutter into some extra flour and cut out scones, being careful not to twist the cutter or touch the edges of the scones (see my notes). Lightly push together any remaining dough and repeat.
Place scones onto a baking tray, brush the tops with milk and sprinkle parmesan cheese on top then bake for 12 - 15 minutes.