Line two baking sheets with parchment paper.
In a small bowl, combine the sugar and orange zest. Using your fingers, massage the orange zest into the sugar. Set aside for 15 minutes.
½ cup sugar, Zest of one orange
In a seperate small bowl, combine the buttermilk, vanilla and egg. Stir with a whisk to combine.
½ cup buttermilk, 1 teaspoon vanilla, 1 egg
In a large bowl, combine the flour, baking soda and salt. Stir with a whisk to combine.
2 ¾ cups flour, ¾ teaspoon baking soda, ½ teaspoon salt
Add the sugar to the flour mixture and stir with a whisk to combine.
Add the butter to the flour mixture. Using a pastry blender, cut the butter into the flour mixture until it resembles coarse crumbs.
½ cup cold butter, cut into small cubes
Add the blueberries to the flour mixture and stir to evenly coat the berries.
1 cup blueberries
Add the buttermilk and gently mix with a fork until combined.
Tranfer mixture to lightly floured surface. Gently knead the dough until it forms a ball, being carful not to handle it too much or squish the blueberries. Pat the dough into an 8-inch round circle.
Using a sharp knife, cut the dough into 8 triangles. Transfer the triangles to one of the prepared baking sheets and place in the freezer for at least 30 minutes.
Preheat the oven to 400°F.
Divide the chilled scones between the two baking sheets and bake in the preheated oven for 18-20 minutes or just until starting to turn golden brown on the tops.
Remove from the oven, allow them to cool for 2 minutes on the baking sheet before transferring to a cooling rack to cool completely.