Preheat your oven to 375°F. Line a baking sheet with parchment paper or a silicone baking mat.

In a large bowl, whisk together the flour, sugar, lemon zest, baking powder, baking soda, and salt. Cut the cold butter into the flour mixture using a pastry blender or your fingertips until it resembles coarse crumbs.

In a small bowl, whisk together the milk, lemon juice, vanilla, and egg. Pour the wet ingredients into the dry ingredients and stir just until combined; do not overmix.

Gently fold in the blueberries.

Turn the dough out onto a lightly floured surface. Knead gently 5 to 6 times until the dough holds together.

Pat the dough into an 8-inch circle. Cut into 8 wedges and place them on the prepared baking sheet, spacing them about 2 inches apart.

Bake for 15 to 20 minutes, until the edges are lightly golden. Transfer to a wire rack to cool completely.

While the scones cool, make the glaze: In a small bowl, whisk together the confectioners' sugar, 2 teaspoons lemon juice, and 2 teaspoons milk until smooth. Adjust consistency with a little more lemon juice or milk if needed.

Dip the tops of the cooled scones into the glaze, or spoon the glaze over them. Sprinkle with a little lemon zest.

Let the glaze set for about 10 minutes before serving. These are best enjoyed the same day.

Store any leftovers in an airtight container in the refrigerator. Let them come to room temperature before serving for the best texture.