Line a baking sheet with parchment paper. Set aside.
Add the flour, baking powder, sugar, and lemon zest to a large bowl and whisk to combine the flour mixture.
Add the cold butter chunks to the mixing bowl and mix with your hands or a pastry blender, ensuring the butter is thoroughly worked into the dry ingredients and the entire mixture is moistened.
Add the milk and lemon juice to the bowl and mix until fully combined and a soft dough is formed.
Turn the scone dough onto a lightly floured surface, form it into a thick disk shape, and place it on the prepared lined baking sheet.
Cut the dough disk carefully into 6 equal triangles using a sharp knife (or pastry cutter).
Bake the scones in the preheated oven for 25 minutes or until lightly golden brown.
Allow the scones to rest on the baking sheet for 10 to 15 minutes before separating them.
Add the powdered sugar, milk, and blackberries to a mixing bowl and mix with a fork, smashing the blackberries as you mix.
Separate the scones, place them on a wire rack, and spread the glaze evenly over the tops of the scones, allowing it to drip down the sides of each scone.
Top the scones with extra blackberries, if desired.
Notes
While scones taste best straight out of the oven, you can store any leftover scones in an airtight container for up to 2 days at room temperature, up to about a week in the fridge, and up to about 3 months in the freezer.Make Ahead Instructions:For making ahead, follow the recipe to the step where you cut the scones, and then put the unbaked scones in the freezer. Place them in an airtight container and freeze them unbaked for up to 1 month. When you’re ready to bake, remove from the freezer and bake from frozen, adding a few extra minutes to the baking time.