Preheat the oven to 350 degrees Fahrenheit and spray two 9" cake pans with cooking spray (I also lined the bottom of the cake pans with parchment paper circles).

In a stand mixer bowl with whisk attachment, add the pumpkin, erythritol, sucanat, egg whites, oil, natural food coloring, stevia extract, butter flavor, and vanilla extract on medium-low speed.

In a medium-sized bowl, whisk together the brown rice flour, oat flour, cocoa, apple pie spice, baking soda, and salt in a bowl.  Add the dry ingredients to the stand mixer.  Scrape down the sides of the bowl, then return to mixing.

Add the almond milk, then add the vinegar.  Pour batter into prepared cake pans, tap pans on the counter to level them out, then bake for ~40 minutes, or until surface springs back when touched. Flip cakes onto wire cooling racks and let cool completely before frosting.

In a small bowl, whisk together the protein powder and cocoa.

In a large bowl, stir together the almond milk, syrup and stevia. Add the dry ingredients and whisk together.  Frost the cake.  Slice and serve!