In a large bowl, whisk together the flour, sugar, lemon zest, baking powder, and salt. Shred the frozen butter and add it to the flour mixture. Blend until crumbly.

In a small bowl, whisk together the cream, egg, and vanilla. Drizzle over the flour mixture and add blueberries. Mix gently.

Turn the dough onto a floured surface and form into an 8-inch disc. Cut into 8 wedges.

Brush with cream and sprinkle with coarse sugar. Refrigerate for at least 15 minutes.

Preheat oven to 400°F (204°C) and bake scones for 22-25 minutes until golden.

Cool and drizzle with a lemon icing made from confectioners' sugar and lemon juice.

Store leftovers at room temperature for 2 days or in the refrigerator for up to 5 days.