01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together flour, sugar, baking powder, salt, and lemon zest.
03 - Add cold butter. Using a pastry blender or your fingertips, cut the butter into the flour mixture until it resembles coarse crumbs.
04 - Gently fold in the blueberries.
05 - In a small bowl, whisk together heavy cream, egg, and vanilla. Pour into the flour mixture and stir until just combined. Do not overmix.
06 - Turn the dough onto a floured surface. Pat into a 1-inch thick circle. Cut into 8 wedges and transfer to the prepared baking sheet.
07 - Brush the tops with a little cream. Bake 18 to 20 minutes, until golden brown. Cool on a wire rack.
08 - While scones bake, make the lemon curd: In a heatproof bowl, whisk lemon juice, zest, sugar, eggs, and salt.
09 - Set over a saucepan of simmering water using the double boiler method, whisking constantly until thickened for about 8 to 10 minutes.
10 - Remove from heat and whisk in butter until smooth. Let cool to room temperature.
11 - Serve scones warm or at room temperature with lemon curd.