These biscuits are the foundation for the decadent apple, rosemary, and caramel shortcakes concocted by Jerry Traunfeld, executive chef of the Herbfarm restaurant in Issaquah, Washington.
Preheat oven to 425 degrees. Line a baking sheet with a Silpat baking mat or a piece of parchment paper. In a medium bowl, sift together flour, baking powder, baking soda, and salt. Stir in 1/4 cup sugar. Cut in the butter using a pastry blender or two knives until the mixture resembles coarse meal. Stir in sour cream and milk. Scoop the dough into six high mounds evenly spaced on the prepared baking sheet. Sprinkle with remaining 2 tablespoons sugar. Bake until lightly browned, about 15 minutes. Transfer the biscuits to a rack to cool slightly before splitting.