01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - Whisk together flour, sugar, baking powder, baking soda, and salt in a large bowl until well blended.
03 - Add cold butter cubes to flour mixture. Cut in using pastry cutter or fingers until mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - Stir chocolate chips into flour-butter mixture until evenly distributed.
05 - Whisk together heavy cream, egg, and vanilla extract in a separate bowl until fully combined.
06 - Pour wet ingredients into dry ingredients. Gently fold with fork until just combined; dough should be shaggy and slightly sticky. Avoid overmixing.
07 - Turn dough onto lightly floured surface. Gently pat into 1-inch thick disc, approximately 7 inches in diameter. Cut into 8 equal wedges and transfer to prepared baking sheet, spacing 2 inches apart.
08 - Brush tops of scones lightly with additional heavy cream for golden finish.
09 - Bake for 16-18 minutes until golden brown and cooked through. Transfer to wire rack and cool completely before glazing.
10 - Whisk powdered sugar, 2 tablespoons milk, and vanilla until smooth. Add remaining milk if needed to achieve drizzling consistency. Drizzle over cooled scones and allow glaze to set before serving.