Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs.
Stir in the orange zest and dried cranberries.
In a separate bowl, whisk together the heavy cream and egg.
Pour the wet ingredients into the dry ingredients and gently stir until just combined.
Turn the dough out onto a lightly floured surface and gently pat it into a 1-inch thick disc.
Use a sharp knife or biscuit cutter to cut the dough into 8 wedges or rounds.
Arrange the scones on the prepared baking sheet.
Brush the tops of the scones with egg wash and sprinkle with turbinado sugar, if using.
Bake for 18-20 minutes, or until golden brown and a toothpick inserted into the center comes out clean.
Let the scones cool on a wire rack before serving.