At least one hour before preparing dough (or the night before), place butter in freezer.
Preheat oven and line a large baking sheet with a silicone baking mat or parchment paper.
Whisk together flour, brown sugar, baking powder, and baking soda.
Grate frozen butter and combine with dry ingredients. Using a pastry blender or a fork, blend butter into flour mixture.
Whisk together sour cream, egg, and vanilla.
Fold sour cream mixture and cinnamon chips into dry ingredients with a rubber spatula. Use hands to continue to lightly knead dough into a ball.
Place dough on a lightly floured surface and dust top of dough ball with a little more flour. Gently shape into a 8-inch round flattened disk and cut into 8 wedges.
Place dough wedges on prepared baking sheet and bake for 16-17 minutes or scones are until lightly golden on top and golden brown on bottom. Serve slightly warm, or cool completely before adding glaze.
Spiced Orange Glaze
Whisk glaze ingredients together until smooth.
Place scones on cooling rack over parchment paper or paper towels to catch drips. Drizzle glaze over cooled scones and allow to set.
Storage and Freezing: Scones are best served the day they're made. If you plan to save for later, they're best stored frozen in an airtight container, for up to 3 months.Cold ingredients: Because we want our scone dough to be flaky, it's important that in addition to the frozen butter, our sour cream and eggs are chilled before adding to the recipe.