Preheat your oven to 400 degrees F (200 degrees C) and line a large baking sheet with parchment paper.
In a large mixing bowl whisk together the flour, sugar, cinnamon powder, baking powder, baking soda, and salt.2½ cups all-purpose flour
Once the dry ingredients are well combined, add the cold cubed butter and work it into the dry ingredient mix, using a pastry cutter or a fork until it looks like coarse crumbs.½ cup unsalted butter
In a separate small bowl whisk together the buttermilk, mashed sweet potato, and vanilla extract. Pour this mixture into the dry ingredients and stir until a crumbly dough begins to form. (Do not overmix!)½ cup cooked mashed sweet potato
Place the dough onto a floured surface and knead until it comes together into a rough ball. Shape the dough into a 7-inch round, then slice it into 8 equal wedges. Arrange the scones on the prepared baking sheet.
Freeze the scones for 30 minutes.
While the scones are freezing, prepare the glaze. In a small bowl whisk together the powdered sugar with the milk until well combined. Set aside.½ cup powdered sugar
When you are ready to bake the scones, remove them from the freezer, and bake for 15 to 20 minutes or until the scones are golden brown.
Let the sweet potato scones cool on a wire rack, then drizzle with the glaze.
Notes
How To Make Mashed Sweet Potatoes:
Baking in the Oven: Prick a medium-sized sweet potato with a sharp knife, place it on a baking tray, and roast it in a hot oven at 400°F for 40-45 minutes. Once soft, peel and mash it with a fork or food processor for smooth sweet potato puree.
Boiling on the Stovetop: Peel and cube your sweet potato, then cook it on medium heat for 15-20 minutes until tender. Drain and mash with a fork, or use a pastry blender for a smoother consistency.