01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and lemon zest until well combined.
03 - Add the cold butter to the flour mixture. Cut it in using a pastry cutter or your fingertips until the mixture resembles coarse crumbs.
04 - In a separate bowl, whisk together the heavy cream, egg, and vanilla extract until smooth.
05 - Pour the wet ingredients into the dry ingredients and stir gently until just combined. Fold in the blueberries carefully to avoid crushing them.
06 - Turn the dough onto a lightly floured surface and gently pat it into a 1-inch-thick circle. Cut into 8 wedges and transfer to the prepared baking sheet, spacing them apart.
07 - Brush the tops with a little extra heavy cream. Bake for 18–22 minutes, or until golden brown. Let cool on a wire rack.
08 - In a small saucepan, whisk together lemon juice, lemon zest, sugar, and eggs. Add butter and cook over medium-low heat, stirring constantly, until thickened (about 8–10 minutes). Do not let it boil. Remove from heat and let cool; it will thicken further as it cools.
09 - Serve scones warm or at room temperature with a generous spoonful of lemon curd.