In a large mixing bowl whisk together flour, brown sugar, white sugar, salt, baking powder, nutmeg and cinnamon.
Grate frozen butter and toss into the dry ingredients. Refrigerate to keep cold.
In a separate bowl whisk together buttermilk, egg, and vanilla.
Toss shredded carrot, walnuts and raisins in flour mixture. Add wet ingredients to dry ingredients, and stir with a spatula until well combined.
Turn out the dough on a floured surface. Using a bench scraper, being to fold the dough, pressing down after each fold, and flouring to keep from sticking.
Form dough into an 8 inch round disk. Use bench scraper to cut disk into eight equal wedges. Transfer wedges to a baking sheet lined with parchment paper. Brush wedges with buttermilk and refrigerate for 15 minutes.
Preheat oven to 400 F. Bake scones for 20-25 minutes. Allow to cool for 5 minutes before moving to a cooling rack.
Schmear each scone with cream cheese frosting and serve.