01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - Whisk together flour, sugar, baking powder, and salt in a large bowl.
03 - Add cold, cubed butter to the dry ingredients and cut in using a pastry cutter or fingertips until mixture resembles coarse crumbs.
04 - Whisk cream, egg, orange zest, and vanilla extract in a separate bowl.
05 - Pour wet ingredients into dry mixture and stir gently until just combined, avoiding overmixing.
06 - Fold the chopped dark chocolate into the dough evenly.
07 - Turn dough onto a lightly floured surface, shape into a 1-inch thick disk, then cut into 8 wedges and place on prepared baking sheet, spaced apart.
08 - Lightly brush scone tops with extra cream and sprinkle turbinado sugar if desired.
09 - Bake for 16 to 18 minutes, until scones are golden brown and cooked through.
10 - Allow scones to cool slightly on a wire rack before serving.