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