Preheat oven to 400°F. Line a large baking sheet with parchment paper and set aside.
Using the fine edge of a box grater, grate the cold butter onto a sheet of parchment paper. Transfer the grated butter to the freezer while preparing the remaining ingredients.
In a large mixing bowl, whisk together the flour, sugar, baking powder, cinnamon, nutmeg, and salt.
Remove the grated butter from the freezer and add it to the bowl with the dry ingredients. Use a fork or pastry blender to gently incorporate the butter until the mixture resembles coarse crumbs.
In a separate medium bowl, whisk together the eggs, vanilla, and eggnog until fully combined.
Pour the wet ingredients into the dry ingredients and stir just until combined. Do not overmix.
Lightly flour your hands and transfer the dough to the prepared baking sheet. Shape the dough into a circle about ¾ inch thick.
Using a bench scraper or large knife, cut the dough into 6-8 wedges (I cut them into 8), gently separating the edges of each scone, creating a ½-inch space between each.
Brush the tops and sides of each scone with eggnog. Sprinkle the turbinado sugar evenly over the tops.
Bake for 15-17 minutes, or until the scones are golden brown and baked through.
Allow to cool on the baking sheet for 5 minutes before transferring to a wire rack.
To make the glaze, whisk together confectioners’ sugar and 1 tablespoon of eggnog. Add more eggnog, a teaspoon at a time, until the glaze reaches your desired consistency.
Drizzle glaze over cooled scones and sprinkle with a pinch of nutmeg.