Step 1: Prepare the Spice Cake

1. Preheat Oven: Set your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans, or line them with parchment paper.
2. Mix Dry Ingredients: In a medium bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, cloves, and allspice.
3. Cream Butter and Sugars: In a large mixing bowl, beat the softened butter with granulated and brown sugars until light and fluffy.
4. Add Eggs and Vanilla: Incorporate the eggs one at a time, thoroughly mixing after each addition. Stir in the vanilla extract.
5. Combine Wet and Dry Ingredients: Alternately add the dry ingredients and buttermilk to the butter mixture, beginning and ending with the dry ingredients. Mix until just combined.

Step 2: Make the Eggnog Buttercream

1. Beat Butter: In a large bowl, beat the butter until smooth and creamy.
2. Add Powdered Sugar and Eggnog: Gradually mix in powdered sugar, then add eggnog and vanilla extract, beating until the frosting is light and fluffy. Adjust consistency with additional eggnog if needed.
3. Add Nutmeg: Optionally, incorporate ground nutmeg for a hint of extra holiday flavor.

Step 3: Assemble the Cake

1. Frost the Cake: Place one layer of the cake on a serving plate and spread with a generous layer of eggnog buttercream. Top with the second layer and apply a crumb coat. Chill briefly, then cover the cake with the remaining buttercream.
2. Decorate: Enhance the cake’s festive look with a dusting of ground nutmeg or festive holiday sprinkles.

Variation

• Fruit Layer: Consider adding a layer of spiced apple compote or cranberry sauce between the cake layers for an added burst of festive flavor.