Add the flour, baking powder, lemon zest, and sugar to the bowl of a food processor fitted with the dough blade. Pulse to combine.

Dice the butter into small cubes and add to the food processor. Process until the butter is worked into the dough leaving small pea sized clumps of butter thoughout.

Remove the mixture to a medium mixing bowl.

In a small bowl, whisk together the milk and sour cream. Add the the flour mixture and stir gently until just combined.

Flour your hands and a work surface. Pat the dough out into a circle on the floured surface to make a 6 inch diameter circle. Cut into 8 equal sized wedges.

Bake in a preheated 400 degree oven for 12-15 minutes or until lightly browned. Let cool.

While the scones are cooling, add the blackberries, granulated sugar, and lemon juice to a small sauce pan over medium heat. Cook for 2-3 minutes, using a fork to smash the berries and release the juice.

Pour berries into a sieve over a small bowl. Press the berries to release the juice.

Whisk the powdered sugar into the berry juice until thick and creamy.

Dip the tops of the scones into the glaze and let sit 5 minutes to harden. Dip a second time for a sweeter amd thicker topping.