Preheat the oven to 350 degrees F. Line the bottom of three 8-inch cake pans with parchment paper and coat with cooking spray.

In a large bowl, combine the flour, granulated sugar, brown sugar, baking powder, baking soda, nutmeg, and salt.

In a separate bowl, whisk together the eggs, vegetable oil, eggnog, and vanilla.

Slowly mix the wet ingredients into the dry ingredients until just combined. Be careful not to overmix.

Pour the batter evenly into the prepared pans.

Bake for 20-25 minutes, or until the cake is light golden brown and a toothpick comes out clean.

Let the cakes cool in the pans for 10 minutes, then invert onto a cooling rack and cool completely.

For the frosting, beat the butter and vanilla extract together until light and fluffy.

Gradually add the powdered sugar, 1 cup at a time, until combined. Beat in the eggnog to achieve a smooth, creamy consistency.

Place one cake layer on a serving plate and spread a thin layer of frosting over it. Add a second layer on top and spread another thin layer of frosting.

Place the third layer on top and cover the entire cake with frosting. Decorate as desired with cranberries and rosemary.

Cut into slices and serve.