Preheat the oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or a silicone baking mat.

1. Make the dry mixture: In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt.
2. Cut in the butter: Add the cubed cold butter to the dry ingredients. Using a pastry cutter or your fingers, cut the butter into the flour mixture until it resembles coarse crumbs with pea-sized pieces of butter.
3. Add the wet ingredients: In a separate small bowl, whisk together the heavy cream, egg, vanilla extract, and lemon zest. Pour the wet ingredients into the flour mixture and stir gently with a spatula until just combined. Be careful not to overwork the dough.
4. Add the blueberries: Gently fold in the blueberries, taking care not to crush them. If you’re using frozen blueberries, it’s best to fold them in directly without thawing to avoid purple streaks in the dough.
5. Shape the dough: Turn the dough onto a lightly floured surface and knead it gently a couple of times to bring it together. Pat the dough into a circle about 1-inch thick.
6. Cut the scones: Using a sharp knife or a pizza cutter, slice the dough into 8 wedges, like a pizza. Arrange the wedges on the prepared baking sheet, spacing them slightly apart.
7. Brush with cream and sprinkle with sugar: Brush the tops of the scones with the remaining tablespoon of heavy cream, then sprinkle them with the extra tablespoon of sugar.
8. Bake the scones: Bake the scones in the preheated oven for 18-22 minutes, or until they are golden brown and cooked through. Allow them to cool slightly on a wire rack.
9. Make the glaze: While the scones are cooling, whisk together the powdered sugar, fresh lemon juice, and lemon zest in a small bowl until smooth and pourable.
10. Glaze the scones: Once the scones have cooled slightly, drizzle the glaze over the top. Let the glaze set for a few minutes before serving.