Preheat oven to 400°F and line a baking sheet with parchment paper.
Whisk the flour, baking powder, baking soda, and salt together in a large bowl.
In a small bowl, whisk the egg and sour cream together.
Pour sugar in another small bowl and press the orange zest into the sugar until combined. Once combined, add the sugar mixture to the flour mixture and mix.
Add the frozen butter and cut it in with a pastry cutter or fork. Work it in well or until the mixture is pea-sized.
Stir in the egg/sour cream mixture with a wooden spoon or with your hands until thoroughly combined and it forms into a ball.
Divide the dough in half. Place balls on lightly floured surface and roll or pat them into a 6-inch circle. Don’t roll it too thin or they will dry out. Cut each circle into 6-8 wedges. We prefer 6 wedges so we can have bigger scones.
Put scones on a parchment lined baking sheet. Keep the scones from touching as they will grow in the oven. Bake for 13-15 minutes, or until golden brown.
While the scones bake, make the glaze.