01 - Preheat the oven to 400°F and 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 blended.
03 - Add cold cubed butter to the dry mixture and cut in with a pastry cutter or fingertips until mixture resembles coarse crumbs with some pea-sized pieces.
04 - In a separate bowl, whisk together heavy cream, egg, vanilla extract, and lemon juice until smooth.
05 - Pour the wet ingredients into the dry mixture and stir gently until just combined; avoid overmixing to maintain tenderness.
06 - Carefully fold fresh or frozen blueberries into the dough.
07 - Turn dough onto a lightly floured surface and pat into a 7-inch round about 1 inch thick.
08 - Cut the dough into 8 equal wedges and arrange them spaced apart on the prepared baking sheet.
09 - Lightly brush the tops of the wedges with additional heavy cream for a golden finish.
10 - Bake in the preheated oven for 16 to 18 minutes until golden brown and cooked through. Transfer to a wire rack to cool.
11 - Whisk powdered sugar, lemon juice, and lemon zest until smooth and slightly runny, then drizzle over cooled scones.