Ingredients
For the Cake

    1 3/4 cups all-purpose gluten free flour
    3/4 teaspoon xanthan gum (omit if your blend contains it)
    2 cups granulated sugar
    3/4 cups cocoa powder*
    2 teaspoons baking soda
    1 teaspoon baking powder
    1 teaspoon fine sea salt
    1 cup buttermilk (or 1 cup unsweetened coconut milk + 1 tablespoon white vinegar)
    1/2 cup avocado oil (or canola oil)
    2 large eggs, room temperature
    2 teaspoons pure vanilla extract
    1 cup hot coffee

For the Frosting

    1 cup butter, softened
    3 cups powdered sugar
    1/2 cup unsweetened cocoa powder
    1 teaspoon vanilla extract
    1/4 cup Almond Milk

Instructions

To make the Cake:

    Preheat oven to 350 degrees and spray 2 8-inch cake pans with non-stick spray. Line the bottom of the pans with parchment paper and spray that parchment paper with non-stick spray.
    In the bowl of a stand mixer, sift together the flour, xanthan gum, sugar, cocoa powder, baking soda, baking powder and salt. Use the paddle attachment to mix the dry ingredients on low speed.
    In a separate bowl, whisk together the eggs, buttermilk, oil and vanilla.
    With the mixer running on low speed, slowly pour the wet ingredients into the dry ingredients. Mix until completely combined.
    Scrape down the sides and bottom of the bowl and pour in the hot coffee. Mix on low until incorporated.
    Pour the batter (it will be very thin and pretty liquidy) evenly between the two pans. Bake at 350 degrees for 35 - 40 minutes. (Mine take about 37 minutes.)
    Cool the cakes on a wire rack (in the pan) for 20 minutes. Carefully remove the cakes from the pans and cool completely on a wire rack.
    When the cakes are cool, prepare the buttercream.

To make the chocolate buttercream:

    Add the butter to the bowl of a stand mixer and beat until completely smooth. Add the powdered sugar and cocoa powder and mix on low to combine. Mix in the vanilla extract and heavy cream.
    Turn the mixer to a medium-high speed and beat for 1-2 minutes or until the frosting is light and fluffy.
    Frost the cake as desired!

Notes

    I currently use my Nightshade Free Flour Mix in this recipe. It also works well with both my White Rice Flour Blend and the Brown Rice Gluten Free Flour Mix. I have also tested this recipe with Bob's Red Mill 1:1 Baking Mix with great results.
    *I use Rodelle's Dutch Processed Gourmet Baking Cocoa because I prefer the rich chocolate flavor. Regular cocoa or dark cocoa powder can also be used.The frosting makes enough to frost one cake. If you would like a thicker layer of frosting or if you want to pipe any details, I suggest making 1 1/2 batches or doubling the recipe.
    If making this dairy free, you can frost this cake with my favorite vegan chocolate frosting.
    Cake adapted from Ina Garten.