• Wash hands with soap and water for 20 seconds.
• Whisk flour, sugar, lemon zest, baking powder, and salt together in a large bowl. Grate the frozen butter and add it to the flour mixture. Combine with a pastry cutter, two forks, or your fingers until the mixture comes together in pea-sized crumbs. Place in the refrigerator or freezer as you mix the wet ingredients together.
• Whisk 1/2 cup milk, the egg, and vanilla extract together in a small bowl. Drizzle over the flour mixture, add the blueberries, then mix together until everything appears moistened.
• Do not taste or eat any raw dough or batter made with uncooked flour and/or raw eggs.
• Pour dough onto the counter and, with floured hands, work into a ball. Dough will be sticky. If it’s too sticky, add a little more flour. If it seems too dry, add 1-2 more Tablespoons milk. Press into an 8-inch disc and, with a sharp knife, cut into 8 wedges.
• Brush scones with remaining milk.
• Place scones on a plate and refrigerate for at least 15 minutes.
• Preheat oven to 400°F.
• Line a large baking sheet with parchment paper or silicone baking mat. After refrigerating, arrange scones 2-3 inches apart on the prepared baking sheet(s).
• Bake for 22-25 minutes or until golden brown around the edges and lightly browned on top. Remove from the oven and cool for a few minutes before topping with lemon icing.

Icing

• Whisk the icing ingredients together. Drizzle over warm scones.
• Leftover iced or un-iced scones keep well in the refrigerator for 5 days.