In a small mixing bowl, combine flaxseed and water and let sit for 5 mins
Preheat oven to 350°
Whisk together flax seed mixture, sugar, and brown sugar
Next, add flour, baking powder, baking soda, cinnamon, nutmeg, salt, vanilla, oil, and applesauce
Fold in carrots, and pour half of the batter into a greased or lined cake pan, and pour the remaining batter into 2nd pan
Place cake pans into the oven to make for 26-30mins
While the cakes are baking, in a medium mixing bowl cream together butter and cream cheese
Next, whisk in powder sugar and brown sugar until icing is an off white color
Remove cakes from oven and allow to cool for 15-20mins
Place cake in serving dish and layer with half of the icing and 2nd cake and top with remaining icing using a spatula
Allow icing to set, slice cake, and serve