Preparation of Dry Ingredients: Begin by sifting together the all-purpose flour, baking soda, cinnamon, cloves, ginger, nutmeg, and salt into a medium bowl. This ensures that the spices and leavening agents are evenly distributed throughout the mixture. Set aside.
Creaming Butter and Sugar: In the bowl of a stand mixer fitted with the paddle attachment, cream together the softened butter and granulated sugar on medium speed until the mixture is light and fluffy, approximately 3 minutes. This process is crucial as it helps to incorporate air into the batter, resulting in lighter cookies.
Incorporation of Wet Ingredients: Add the egg and molasses to the creamed butter and sugar, continuing to beat on medium speed until fully integrated. The molasses provides moisture and a rich, caramel-like flavor, while the egg acts as a binder for the cookie dough.
Combining Wet and Dry Mixtures: Gradually add the dry ingredient mixture to the wet ingredients in the stand mixer, beating on low speed just until the dough comes together without overmixing.
Chilling the Dough: Cover the bowl containing the cookie dough and refrigerate for 1 hour. Chilling the dough is essential as it allows the ingredients to meld together and also makes the sticky dough easier to handle during shaping.
Preheating the Oven: Preheat the oven to 375 degrees Fahrenheit (190 degrees Celsius). This high temperature is vital for achieving the characteristic cracks on the surface of the cookies.
Shaping and Sugaring: Once chilled, remove the dough from the refrigerator. Using a spoon, scoop out portions of the dough and roll into 1-inch balls. Roll each ball in granulated sugar to coat completely, which will give the cookies their distinctive sparkly appearance.
Baking the Cookies: Arrange the sugared dough balls on a baking sheet lined with parchment paper, spacing them at least 1 inch apart. Bake in the preheated oven for 8-10 minutes, or until the cookies begin to crack on top but are still soft in the center.
Cooling: Remove the cookies from the oven and transfer them to a wire rack to cool completely. It is crucial to allow them to cool before assembling with buttercream to prevent the frosting from melting.
Making the Eggnog Buttercream: While the cookies cool, prepare the eggnog buttercream. In the clean bowl of the stand mixer, beat the softened butter until fluffy. Gradually add powdered sugar, vanilla extract, and nutmeg, continuing to beat until smooth. Finally, add eggnog gradually, adjusting the quantity of powdered sugar as needed to achieve a thick, spreadable consistency.
Assembly: Once the cookies are completely cooled, pair them by size. Pipe or spread a generous amount of eggnog buttercream on the flat side of one cookie of each pair, then gently press the second cookie on top to form a sandwich. This method ensures a balanced ratio of cookie to buttercream, enhancing the overall flavor and texture.