Preheat the oven to 400?F (200?C) and line a baking sheet with parchment paper.

In a mixing bowl, whisk together the gluten-free flour, baking powder, sugar, and salt.

Add the cold butter to the flour mixture and use a pastry cutter to blend until the mixture resembles coarse crumbs.

In a separate bowl, whisk together the egg and milk.

Pour the wet ingredients into the dry ingredients and mix until just combined.

Gently fold in the blackberries, being careful not to crush them.

Turn the dough out onto a lightly floured surface and pat it into a circle about 1 inch thick.

Cut the dough into wedges and place them on the prepared baking sheet.

Bake for 15-20 minutes or until golden brown.

Allow the scones to cool slightly before serving. Enjoy warm or at room temperature.