In a large bowl, whisk together the flour, sugar, lemon zest, baking powder, and salt.

Grate the frozen butter using a box grater and add it to the flour mixture.

Combine using a pastry cutter, two forks, or your fingers until the mixture forms pea-sized crumbs.

Place the bowl in the freezer to keep the butter cold while you prepare the next ingredients.

In a small bowl or liquid measuring cup, whisk together ½ cup of heavy cream, the egg, and vanilla extract.

Remove the flour and butter mixture from the freezer.

Drizzle the cream mixture over it, add the blueberries, and gently mix with a spatula or wooden spoon until the dough appears moistened and just combined.

Lightly flour a work surface or counter.

Pour the dough onto the floured area and, using floured hands, form the dough into a ball.

Press the dough into an 8-inch disc, about 1 inch thick, and use a sharp knife or bench scraper to cut the disc into 8 wedges.

In a small bowl, mix the remaining 1 tablespoon of cream with a bit of water, then brush this mixture over the scones.

Place the scones on a plate or lined baking sheet and refrigerate for at least 15 minutes, or up to 24 hours.

Preheat your oven to 400°F (204°C).

Line a large baking sheet with parchment paper or a silicone baking mat.

Arrange the chilled scones 2–3 inches apart on the prepared baking sheet.

Bake for 22–25 minutes, until they are golden brown around the edges and lightly browned on top.

Remove from the oven and allow them to cool for 5 minutes before adding the icing.

In a small bowl or liquid measuring cup, whisk together the confectioners’ sugar and 2 tablespoons of lemon juice.

Drizzle the lemon icing over the warm scones.