In a bowl of a stand mixer with the paddle attachment or a large mixing bowl with a hand mixer, beat the eggs, brown sugar and granulated sugar on medium speed for 3-4 minutes, until the mixture is fluffy and lighter in color. Add the oil and vanilla extract, and beat the mixture for about 30 seconds. Add in the sour cream and buttermilk and mix until incorporated. Add in all of the spices, the baking powder, baking soda and salt, then add the flour 1 cup at a time, scraping down the sides of the bowl as needed. After adding the last portion of flour, beat the batter just until combined. Spray a mini gingerbread shaped pan with baking spray. Fill each of the 6 wells 1/2-2/3 of the way to the top. Half of the batter should be used. Set aside the remaining batter. Bake at 350 degrees for 25-30 minutes, until a toothpick inserted in the center of each and comes out clean or with a few crumbs. Cool on a wire rack for about 10 minutes, then gently flip the pan over to remove the cakes. Spray the pan again and fill each well with the remaining batter and repeat the process. Cool completely.
Icing
In a small bowl, add powdered sugar, vanilla and 2 tablespoons of milk. Whisk until smooth. If the mixture is too thick, add an additional tablespoon of milk. Add icing to a piping bag. Cut off a very small area at the end of the bag, about 1/8-1/4 inch. Add icing to the tops of the cakes, so it looks like snow. Pipe small dots of frosting on the fronts of the cakes for additional decor.