In a large mixing bowl, sift together the all-purpose flour, baking powder, baking soda, ground cinnamon, ground ginger, ground nutmeg, and salt until well combined.

In a separate bowl, whisk together the sugar, eggs, milk, vegetable oil, and vanilla extract until smooth.

Gradually incorporate the dry ingredients into the wet mixture, stirring until you achieve a smooth, lump-free batter.

Preheat your oven to 350°F (175°C) and grease two 9-inch round cake pans.

Divide the spice cake batter evenly between the prepared pans and smooth the tops with a spatula.

Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Allow them to cool in the pans for about 10 minutes before transferring to a wire rack.

While cakes cool, prepare the eggnog buttercream. Beat softened butter until creamy, then gradually add powdered sugar and mix until combined.

Slowly pour in eggnog and mix until smooth and fluffy. Mix in ground nutmeg.

Place one layer of the cooled cake on a plate, spread a generous layer of eggnog buttercream on top.

Gently position the second layer on top and frost the entire cake with remaining buttercream.

Decorate with festive sprinkles, cinnamon sticks, or additional ground nutmeg as desired.