Instructions:
- Whisk together the flour, granulated sugar, baking powder, and salt in a large bowl.
- Add the cold, cubed butter to the dry ingredients. Use a pastry blender or your fingertips to rub the butter into the flour until the mixture resembles coarse sand with some pea-sized pieces remaining.
- Gently fold in the fresh blueberries, being careful not to crush them excessively.
- In a separate small bowl, whisk together the heavy cream and the lightly beaten egg.
- Pour the wet mixture into the dry ingredients. Mix very briefly with a fork until just combined. The dough should look shaggy and slightly sticky—do not overmix!
- Turn the shaggy dough out onto a lightly floured surface. Gently press it together into a rough square or rectangle, about 1 inch thick. Wrap tightly and chill in the refrigerator for 30 minutes.
- After chilling, gently roll or press the dough to about ¾-inch thickness. Use a 2 ½-inch round cutter to stamp out 8 scones. Press straight down and lift straight up without twisting the cutter.
- Place the cut scones onto a baking sheet lined with parchment paper. Brush the tops lightly with the egg wash mixture and sprinkle generously with coarse sugar.
- Bake in a preheated oven at 400°F (200°C) for 15–18 minutes, or until the scones have risen high and the tops are golden brown.
- Transfer immediately to a wire rack to cool slightly before serving warm with clotted cream and jam.