01 - Preheat the oven to 400°F and line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, baking powder, salt, and black pepper.
03 - Add cold, cubed butter and rub into the flour mixture using fingertips or a pastry cutter until coarse crumbs form.
04 - Stir in grated sharp cheddar cheese and chopped chives evenly into the mixture.
05 - Whisk together whole milk and sour cream in a separate bowl.
06 - Pour wet ingredients into dry mixture and gently fold with a fork until just combined, avoiding overmixing.
07 - Turn dough onto a lightly floured surface and pat into a 1-inch thick round.
08 - Slice the dough into 8 wedges and arrange on the prepared baking sheet.
09 - Brush scone tops with milk and sprinkle with extra grated cheddar if desired.
10 - Bake for 16 to 18 minutes until golden brown, then allow to cool slightly before serving.