01 - Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
02 - In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, baking powder, salt, and finely grated lemon zest.
03 - Add the cold, cubed unsalted butter to the dry ingredients. Utilizing a pastry cutter or your fingertips, work the butter into the flour mixture until it achieves a coarse, crumb-like consistency.
04 - In a separate bowl, whisk together the heavy cream, large egg, and pure vanilla extract.
05 - Pour the wet ingredients into the bowl with the dry ingredients. Gently mix with a spatula until just combined; be careful not to overmix.
06 - Gently fold the fresh or unthawed frozen blueberries into the dough.
07 - Turn the dough onto a lightly floured surface and pat it into a disc approximately 7 inches (18 cm) in diameter and 1 inch (2.5 cm) thick.
08 - Divide the disc into 8 equal wedges and arrange them on the prepared baking sheet, ensuring adequate spacing between each scone.
09 - Lightly brush the tops of each scone with a small amount of additional heavy cream.
10 - Bake for 16–18 minutes, or until the scones are lightly golden brown and fully cooked through.
11 - Allow the scones to cool on a wire rack for 10 minutes.
12 - For the optional glaze, combine powdered sugar with 1–2 tablespoons of fresh lemon juice until a thick yet pourable consistency is achieved. Drizzle this glaze over the warm scones.