Ingredients for 15 scones:
3 1/2 cups unbleached flour
4 ounces unsalted butter at room temperature
2 tablespoons sugar
1 tablespoon baking powder
1 teaspoon fine sea salt
1 cup plus 3 tablespoons milk
Yolk of 1 egg
Preheat the oven to 375 degrees. Line a bake sheet with parchment or butter and flour it.
Thoroughly mix the dry ingredients: flour, sugar, baking powder and salt in the bowl of a mixer, food processor or mixing bowl. Cut up the butter into small pieces and blend it into the dry ingredients until the texture is granular.
Turn this mixture into a bowl and slowly incorporate the milk with a fork. Gather the dough into a ball and place it on a lightly floured work surface. Dust the dough lightly with flour and roll it out 1/2" thick. Use a cookie cutter or the rim of a glass to cut circles in the dough. Lift biscuits onto the bakesheet. Stir a few drops of milk into the egg yolk and coat the top of each scone with this wash.
Bake for 15 minutes, until the scones are fully risen and lightly browned. Cool on a rack.