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