Vanilla Brown Sugar Eggnog Cookies

1. In a large mixing bowl, beat together the butter and brown sugar. Add the egg and mix until combined. Beat in the bourbon (if using) and vanilla. Add the flour, cinnamon, nutmeg, baking soda, and salt, beat until combined and the dough forms a ball. If the dough feels too wet to roll out, add 2-4 tablespoons of additional flour.
2. Preheat the oven to 350° F. Line a baking sheet with parchment paper.
3. Divide the dough in half. Roll out the dough on a floured piece of parchment paper to 1/4 inch thickness. Make sure you're using enough flour, or your dough will stick. Cut out the shapes using holiday cookie cutters such as Christmas trees, snowflakes, and The Grinch. Transfer the cookies to a parchment-lined baking sheet. I recommend using a floured spatula to lift the cookies. Cover the baking sheet and place in the freezer until firm, 15 minutes. Roll out the leftover scraps, and repeat with the remaining dough.
4. Bake the cookies on the middle rack of the oven for 8-10 minutes or until just lightly golden. Let cool.
5. Meanwhile, make the icing. In a medium bowl, whisk together the powdered sugar, vanilla, and nutmeg. Add 1 tablespoon eggnog (or water/milk) until smooth and drizzly. If needed, thin the glaze by adding more water – 1 tablespoon at a time, until drizzly. 
6. Decorate each cookie as desired with vanilla icing, sprinkles, and or vanilla sugar.
To Make Snowflakes: Pipe lines and dots of frosting onto each cookie to enhance the snowflake shape (see photos for visuals). If desired, sprinkle with vanilla sugar. Let the frosting set before serving, about an hour.
To Make Christmas Trees: Fill in each tree with vanilla frosting, then sprinkle with vanilla sugar.
For the Grinch: I filled in his eyes with edible gold dust, then used black dyed icing for his eyebrows and mouth. I filled in his face with green dyed icing.