Grease three 8-inch cake pans and line the bottoms with parchment paper.
Mix dry ingredients:
In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, and cloves. Set aside.
Cream the butter and sugars:
In a large bowl, beat butter, granulated sugar, and brown sugar until fluffy (3-4 minutes).
Add eggs and vanilla:
Beat in the eggs one at a time, followed by the vanilla extract.
Combine wet and dry ingredients:
Alternate adding the dry ingredients and buttermilk to the butter mixture. Start and finish with the dry ingredients. Stir in the applesauce.
Bake:
Divide the batter evenly among the pans and bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes in the pans, then transfer to a wire rack.
Make the buttercream:
Beat butter until creamy. Slowly add powdered sugar, followed by eggnog, vanilla, and nutmeg (if using). Mix until smooth and fluffy.
Assemble the cake:
Place the first cake layer on a plate and spread a layer of buttercream. Repeat with the remaining layers, then frost the sides lightly for a “naked cake” effect.
Decorate:
Garnish the top with cranberries, star anise, cinnamon sticks, and sprigs of rosemary. Dust with powdered sugar for a snowy effect.