Preheat your oven to 325°F (163°C) and grease and flour two 8-inch round cake pans.

In a large mixing bowl, combine cake flour, sugar, baking powder, salt, nutmeg, and cinnamon. Whisk until well mixed.

In another bowl, whisk together eggnog, milk, vegetable oil, rum extract, and eggs until fully blended.

Add softened butter to the dry ingredients and blend until the mixture resembles coarse crumbs.

Mix one-third of the wet mixture into the butter-flour blend and then add the remaining in two parts, mixing until just combined.

Divide the batter evenly between the prepared cake pans and smooth the tops.

Bake for 50-55 minutes until edges pull away and a toothpick comes out clean. Allow cakes to cool in pans for 10 minutes, then transfer to wire racks.

While cooling, whip softened butter for the buttercream until fluffy. Gradually add confectioner’s sugar, then mix in milk, vanilla, salt, and nutmeg.

Once cooled, frost the top of one cake layer with eggnog buttercream, place the second layer on top and frost the entire cake.