Preparation
1-Preheat your oven to 220°C (425°F): Preheat your oven to 220°C (425°F). Position your oven rack in the middle for even baking.
2-Line a baking sheet with parchment paper: Line a baking sheet with parchment paper or a silicone baking mat.

Make the Scone Dough
3-In a large mixing bowl, sift together: In a large mixing bowl, sift together 250g self-raising flour, 1 tsp baking powder, 1/4 tsp salt, and a pinch of cayenne pepper. If using mustard powder, sift it into the mixture for an extra hint of warmth and depth.
4-Add 75g of cold, cubed butter to: Add 75g of cold, cubed butter to the dry ingredients. Use a pastry blender, a fork, or your fingertips to work the butter into the flour mixture until it resembles coarse crumbs. Stir 150g of grated cheddar cheese into the crumbly flour mixture.
5-In a separate bowl, whisk together 125ml: In a separate bowl, whisk together 125ml of milk and 1 large egg. Make a well in the centre of the dry ingredients and pour in the wet mixture.

Mix and Shape the Dough
6-Mix until just combined to form a: Mix until just combined to form a sticky dough. Be careful not to overmix, as this will make the scones tough.
7-Turn the dough onto a lightly floured: Turn the dough onto a lightly floured surface and knead gently a few times.
8-Shape the dough into a round disc: Shape the dough into a round disc about 2 cm thick. Use a round cookie cutter to cut out 8 scones, or simply cut the disc into 8 wedges.

Bake
9-Place the cut scones on the prepared: Place the cut scones on the prepared baking sheet.
10-Optional: Optional: Brush the tops with a little milk for a shiny finish.
11-Bake for 15-20 minutes, or until the: Bake for 15-20 minutes, or until the scones are golden brown on top. Remove from the oven and transfer to a wire rack to cool slightly.