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.
03 - Add cold cubed butter to the flour mixture. Using a pastry cutter or fingertips, work the butter into the flour until the mixture resembles coarse crumbs.
04 - Gently fold blueberries into the dry mixture.
05 - In a separate bowl, whisk together heavy cream, egg, and vanilla extract until combined.
06 - Pour wet ingredients into dry mixture. Stir gently with a spatula until just combined, avoiding overmixing.
07 - Turn dough onto a lightly floured surface. Pat into a 7-inch round disc approximately 1 inch thick.
08 - Cut the dough round into 8 equal wedges. Arrange wedges on prepared baking sheet with space between each scone.
09 - Brush the tops of scones with additional cream if desired.
10 - Bake for 16 to 18 minutes until golden brown and cooked through. Transfer to wire rack to cool.
11 - In a small bowl, whisk together sifted powdered sugar, lemon juice, and lemon zest until smooth.
12 - Drizzle glaze over cooled scones before serving.