Mix flour, 1/3 cup sugar, baking powder, baking soda, and salt in a bowl. Grate frozen butter into flour mix. Work with fingers until mixture resembles coarse meal.

Mix sour cream with lemon zest and egg in a small bowl. Stir into flour mixture with blackberries. Stir until dough comes together, don’t worry if berries become slightly crushed.

Line a cookie sheet with parchment paper. Turn dough out onto paper and form into a 7 inch round. Cut into 8 wedges. Separate slightly. If you can’t separate dough at first, bake for 15 minutes and then gently separate scones so the interiors will cook. Sprinkle evenly with sugar

Bake at 400 20-25 minutes until done. Drizzle with lemon glaze