¾cup(170 g or 1 1/2 sticks) unsalted butter, room temperature
½cup(100 g) granulated sugar
½cup(100 g) packed light brown sugar
2large egg yolks, room temperature
1teaspoonpure vanilla extract
½teaspoonrum extract
½cupeggnog, room temperature
Frosting
½cup(113 g or 1 stick) unsalted butter, room temperature
2-4Tablespoonseggnog, room temperature
½teaspoonrum extract
2 ½cups(300 g) confectioners' sugar
Instructions
Cookies
In a medium bowl, whisk together flour, baking powder, salt, nutmeg and cinnamon. Set aside.
In the bowl of an electric stand mixer (or using a hand mixer), mix butter, granulated sugar and brown sugar until light and fluffy, about 3 minutes. Add egg yolks one at a time, mixing just until combined. Add vanilla extract, rum extract and egg nog and mix until incorporated.
With mixer set on low speed, slowly add in dry ingredients and mix just until combined (avoid over mixing).
Scoop dough out by heaping tablespoonfuls, gently roll into a ball and place on prepared baking sheet. Space cookies 2-inches apart. Place cookie sheet in the refrigerator while oven preheats to 350° F.
Bake at 350° F for 10 to 12 minutes or until edges are golden. Cool on baking sheet for 5 minutes before transferring to a wire rack to cool completely.
Frosting
In the bowl of an electric stand mixer (or using a hand mixer), beat butter until light and creamy, about 3 minutes. Mix in rum extract and 2 tablespoons eggnog. With the mixer on low, slowly add powdered sugar. If necessary, add more eggnog one tablespoon at a time to reach desired consistency.
Use an offset spatula to spread frosting on cooled cookies. Sprinkle lightly with nutmeg if desired.
Notes
Eggnog: It's best to use store-bought (I prefer the Southern Comfort brand). Homemade eggnog can greatly vary in the amount of sugar added, which can affect the texture of the cookies.Rum extract substitute: You may substitute rum extract for the real thing - 1 teaspoon white rum or use only vanilla extract.Make ahead the dough and store covered in the refrigerator for up to 48 hours. Frosting may also be covered and chilled for up to 1 week.Store cookies in an airtight container at room temperature for 3 days or in the refrigerator for up to 5 days. Serve at room temperature.Freeze dough for up to 3 months. Let dough defrost in the refrigerator before bringing to room temperature and baking. Frosting may also be stored in the freezer. After it's defrosted, mix it for 10 seconds to get a smooth consistency.