Preheat oven to 350 degrees.
Combine butter and sugars in stand mixer (or in a bowl with an electric mixer) and cream on medium high until light and fluffy. About 3-4 minutes. Add in eggs, one at a time, and cream more until well combined. About another 2 minutes. Add in vanilla.
Combine white rice flour, tapioca starch, xanthan gum, cocoa powder, baking soda and salt in a separate bowl and toss to combine.
Alternatively add in dry mixture and milk/coffee, starting and ending with the dry mixture.
Grease 2 9-inch round baking pans with butter or non-stick cooking spray and divide batter evenly among them.
Bake for 22-25 minutes, or until toothpick comes out clean.
Peanut Butter Frosting While baking cakes, combine 4 T. butter and ½ c. peanut butter and cream until well mixed. Alternatively add powdered sugar and milk until all ingredients have been used.
Your frosting can vary in consistency depending on what type of peanut butter you use. Add more milk if you have a dry frosting and more powdered sugar if your frosting is not stiff enough.*
Remove cooked cakes from pans to allow for quicker cooling once they have been out of the oven for at least 10 minutes.
To assemble cake, place a dollop of frosting on the plate your are placing it on. Put the first layer down. Spread about 1/3 of the frosting mixture over the first layer. Add in 3-4 toothpicks to allow for greater stability. Place second cake layer on top of the first frosted layer. Completely frost the top and sides of the cake with the remaining frosting.
Dark Chocolate Ganache
Bring 1 c. of heavy whipping cream to a rolling boil and remove from heat. Add in entired bag of dark chocolate chips, stir once and then let sit undisturbed for 5-7 minutes. Stir ganache until smooth. Let chill for another 5 minutes and then start spreading over frosted cake. This part gets pretty messy. If you can, place waxed paper or aluminum foil under the edges of the cake to catch run-off ganache. Enjoy!