Grease and flour three 9-inch cake pans and set aside. Preheat oven to 350° F.

Whisk together dry ingredients (flour through nutmeg) in a medium bowl and set aside.

In a large mixing bowl, cream softened butter with a hand mixer. Add sugars and mix on high for about 2 minutes until well creamed together.

Add eggs, 2 at a time, mixing on medium until just combined. Add molasses and vanilla, mixing until combined.

Mix in 1/3 of the flour mixture on low speed, followed by 1/3 of the buttermilk. Repeat until all are mixed in and just incorporated.

Evenly distribute batter between prepared pans. Bake for 20-24 minutes, until a toothpick comes out clean or with moist crumbs. Let cakes cool in pans for 10 minutes, then invert onto cooling racks to cool completely.

For the sugared cranberries and rosemary, mix water and 1/2 cup sugar in a pot, bring to a boil, then remove from heat to cool slightly.

Dip rosemary in the mixture and let dry for 15 minutes. Add cranberries to the mixture and let sit for 10 minutes. Then roll in granulated sugar and set to dry for 10 minutes.

For the frosting, cream softened butter in a large mixing bowl. Beat in 2 cups powdered sugar with milk, vanilla, and salt.

Gradually mix in the remaining powdered sugar and then add mascarpone and cream cheese.

To assemble, place one cake layer on a cake stand and spread with 1 and 1/4 cups of frosting. Pipe a border of frosting, add 1/2 cup cranberry jam inside the border, and then add the second cake layer. Smooth the frosting and chill for 10-15 minutes.

Repeat with the second layer, then add the top layer upside down. Use remaining frosting to cover the top and apply decorative frosting on the sides.

Create swirls on the top and decorate with sugared rosemary trees and cranberries. Sprinkle with white sanding sugar for decoration.

Chill the assembled cake for at least 30 minutes before slicing and serving.