Cheese & Chive Scones with Buttermilk

Preheat oven to 220C/200CFan/430F.
Place the flour, salt, cayenne pepper and mustard powder into a large mixing bowl and give it a mix to combine.
Add the cubed butter and lightly rub through your finger tips until the butter has been combined and the mixture resembles breadcrumbs.
Stir through 125g (4.4 oz) of the grated cheese and the chopped chives.
In a separate bowl, whisk together the buttermilk and egg. Add the buttermilk mixture to the flour mixture and using your hands, or a knife gently bring it together.
If the dough feels too dry, you can add a little extra buttermilk to the mixture.
It's important not to overwork the scone mixture, otherwise you will have a heavy, dense scone.
Bring the scone mixture into a ball, without needing, and turn onto a lightly floured surface. Roll gently until 3cm (1 ¼-inch) thick and cut into rounds using a 6.5cm (2 ½-inch) diameter pastry cutter.
When cutting scones, push the cutter straight down without twisting it about. If you twist the cutter your scones won't rise as well.
Place the scones well apart on a lined baking sheet.
Brush the top of each scone with a beaten egg or milk wash. Sprinkle the top of each scone with some of the remaining cheese.
Place on the middle shelf of the oven, and bake for 16-18 minutes until the top is golden and the cheese bubbles.
Remove from the oven and set the scones onto a wire rack to cool for 10 minutes and serve warm.