Preheat your oven to 350 degrees and grate your carrots and melt the coconut oil.
In a small mixing bowl, whisk together all-purpose flour, whole wheat flour, baking soda, salt. cinnamon and ground ginger.
In a stand mixer (or mixing bowl and whisk) on low, combine the oil, sugar, and sourdough starter. Add in your eggs, vanilla and carrots until everything is well incorporated. Add the dry ingredients into the wet ingredients, mixing until combined.
Pour the batter into a greased 9x13 baking dish.
Bake at 350 degrees for 35-40 minutes until a tooth pick comes out clean from the middle.
Sit and let cool completely before adding the cream cheese frosting.
In the stand mixer on low, whip together butter, cream cheese, powdered sugar, and add milk until you've reached your desired constancy.
Spread evenly over the carrot cake. Place into the fridge until ready to serve.
