01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
03 - Add cold, cubed butter to dry ingredients. Cut in using a pastry cutter or fingertips until mixture resembles coarse crumbs.
04 - In a separate bowl, whisk buttermilk, egg, and vanilla extract until combined.
05 - Pour wet mixture into dry ingredients. Add chocolate chips and gently stir until just combined to avoid overmixing.
06 - Turn dough onto a lightly floured surface and pat into an 8-inch diameter circle about 1 inch thick.
07 - Cut dough into 8 wedges and place them spaced apart on the prepared baking sheet.
08 - Bake for 16 to 18 minutes until golden brown. Remove from oven and let cool slightly.
09 - Whisk powdered sugar, 2 tablespoons milk, and vanilla in a small bowl. Add additional milk as needed to achieve a thick, pourable consistency.
10 - Drizzle glaze over warm scones and allow it to set a few minutes before serving.