Preheat your oven to 425°F (220°C).
In a large bowl, whisk together flour, sugar, baking powder, and salt.
Add the cold, cubed butter and mix until crumbly.
Gently fold in the blueberries.
In a separate bowl, mix the heavy cream and vanilla extract.
Pour the cream mixture into the dry ingredients.
Stir until just combined; do not overmix.
Turn the dough onto a floured surface and knead gently.
Pat the dough into a circle about 1-inch thick.
Cut into wedges and place on a baking sheet lined with parchment paper.
Brush with egg wash for a golden finish.
Bake for 15-20 minutes until golden brown.