In a large bowl, stir together flour, granulated sugar, salt, cinnamon, and nutmeg. Using a fork or pastry blender, cut cold butter into flour mixture until mixture resembles coarse crumbs with some pea-size pieces of butter remaining. Add Eggnog, stirring until combined.
On a lightly floured surface, roll dough to ¾-inch thickness. Using a 3-inch round cutter dipped in flour, cut biscuits from dough and place on prepared pan 2 inches apart.
Brush tops of biscuits with egg and sprinkle evenly with turbinado sugar. Bake for 8 minutes. Reduce oven temperature to 375°. Bake until golden brown, about 15 minutes more.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/eggnog-biscuits/