Place granulated sugar in a large bowl and zest the orange directly over it. Use your fingers or rubber spatula to rub the orange zest into the sugar, releasing the oils and flavoring the sugar.
Add in the flour, .baking powder, baking soda, and kosher salt and mix well.
Toss cold, cubed butter into the dry ingredients and then grab the butter and flour together, using a finger snapping motion.
Alternatively, you can cut in the butter by pulsing in the food processor. You should end up with a coarse texture with lumps of butter no larger than peas.
Whisk together, buttermilk, and egg, and about a tablespoon of orange juice.
Pour the wet ingredients into the dry ingredients and begin stirring with a rubber spatula or wooden spoon.
When about halfway combined, add in your frozen cranberries and stir until uniformly distributed. There will still be dry pockets of flour on the bottom of the bowl.
Dump your shaggy dough onto a lightly floured work surface and use a bench scraper, or your hands to fold the dough over onto itself two or three times, incorporating all the dry ingredients.
Use your hand to form the dough into a smooth ball. Flatten it out to a disc about 6 to 8 inches in diameter.
Use a sharp knife or bench scraper dipped in flour, to cut your scone dough into eight wedges. Place them on a parchment paper lined sheet pan and put in the freezer while you preheat your oven to 400°F.
When the oven is preheated, remove the scone wedges from the freezer and brush with more buttermilk or with egg wash consisting of one egg whisk with one tablespoon of water or milk.
Bake at 400°F for 18 to 22 minutes or until fluffy and golden brown on top. Cool on the tray for at least 10 minutes while you make your glaze.