01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, baking soda, salt, and lemon zest until well combined.
03 - Add the cold butter to the flour mixture and cut it in using a pastry cutter or your fingers until the mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - In a small bowl, whisk together the cream, egg, and vanilla extract until fully blended.
05 - Pour the wet ingredients into the dry mixture and stir gently with a spatula just until combined. Do not overmix—the dough should be slightly shaggy.
06 - Gently fold in the blueberries, being careful not to crush them.
07 - Turn the dough onto a lightly floured surface. Gently pat it into a 7–8 inch circle, about 1 inch thick.
08 - Cut the circle into 8 equal wedges. Transfer to the prepared baking sheet, spacing them about 2 inches apart.
09 - Lightly brush the tops of each scone with a small amount of extra cream.
10 - Bake for 18–22 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out clean.
11 - Let the scones cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
12 - While scones cool, whisk together powdered sugar, 2 tablespoons of milk or cream, and vanilla extract until smooth and pourable. Add more liquid if needed to reach desired consistency.
13 - Drizzle the glaze over the cooled scones and serve immediately.