01 - Preheat 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 evenly combined.
03 - Add cold butter cubes to the flour mixture. Using a pastry cutter or fingertips, work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - In a separate bowl, whisk together cream, egg, vanilla extract, and lemon juice until fully blended.
05 - Pour the wet ingredients into the flour mixture. Stir gently until just combined to ensure a tender texture; do not overmix.
06 - Gently fold the blueberries into the dough, taking care not to crush them.
07 - Turn the dough onto a lightly floured surface. Pat it into a 7-inch round disc, approximately 1 inch thick.
08 - Cut the round into 8 equal wedges. Arrange the wedges on the prepared baking sheet, leaving space between them for expansion.
09 - Lightly brush the tops of the scones with a thin layer of heavy cream.
10 - Bake for 16 to 18 minutes, or until the tops are golden brown and a toothpick inserted into the center comes out clean. Transfer to a wire rack to cool.
11 - Whisk together powdered sugar, lemon juice, and lemon zest until the mixture is smooth and slightly runny.
12 - Drizzle the citrus glaze generously over the cooled scones before serving.