01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, and salt.
03 - Add cold, cubed butter to the dry mixture and cut in with a pastry blender or fingers until it resembles coarse crumbs.
04 - Whisk together heavy cream, egg, and vanilla extract in a separate bowl.
05 - Pour wet ingredients into dry mixture and stir gently until just combined.
06 - Gently fold in semisweet chocolate chips, avoiding overmixing.
07 - Turn dough out onto a lightly floured surface and pat into a 7-inch (18 cm) circle about 1 inch thick.
08 - Cut dough into 8 wedges and place them on the prepared baking sheet.
09 - Brush tops of wedges with additional heavy cream for a golden finish.
10 - Bake for 16 to 18 minutes, until golden brown and set.
11 - Transfer scones to a wire rack and cool for 10 minutes.
12 - Whisk powdered sugar, milk or cream, and vanilla extract until smooth; drizzle over warm scones.