Prepare the ingredients. In a large mixing bowl, whisk together the 250 g all-purpose flour, 100 g sugar, 10 g baking powder and 1/2 tsp. salt.
Grate the frozen 115 g unsalted butter using a grater directly into the flour mixture. Quickly work the grated butter into the flour until the mixture resembles coarse crumbs with pea-sized pieces. Do not overwork. Keep it crumbly and cold.
The Wet
In a small bowl, whisk together the 120 ml heavy cream, 1 egg, and 1-2 tsp. vanilla extract until combined.
The Dough
Pour the wet mixture over the dry ingredients. Add your 150-250 g blueberries. Gently fold with a spatula until just moistened and the dough begins to come together. Do not overmix.
Turn the dough out onto a floured surface. With floured hands, gently knead the dough 3-4 times until it forms a rough ball.
Flatten into a disc about 20 cm (8 inches) in diameter. Cut into 8 triangles with a sharp knife.
Place the wedges on a baking sheet with parchment paper and in the refrigerator for at least 15 minutes to prevent over-spreading and to keep them flaky.
The Baking
Preheat the oven to 400°F (204°C). Lightly brush the tops with the 2 Tbsp. heavy cream. For extra crunch, sprinkle with 1-2 tsp. turbinado sugar.
Bake on a parchment-lined baking sheet for 20-25 minutes, until golden brown and crisp on the edges.
The Serving
Allow to cool slightly before serving. Enjoy your warm Blueberry Scones [Scones aux bleuets].