- Combine the American Almond® blanched almond flour, rice flour, cocoa powder, tapioca starch, baking soda, salt and xanthan gum. Set aside.
- In a large mixing bowl, cream together the butter and brown sugar until lightened. Beat in the egg and vanilla extract.
- Add the dry ingredients alternating with the buttermilk in two additions. Mix until combined. Stir in the vinegar.
- Let the batter sit for 15 minutes.
- Using a #30 (1 ounce) portion scoop, portion the batter into mounds spaced 4 inches apart on paper-lined baking sheets.
- Bake at 350°F until the cakes are set and spring back when lightly touched, about 15 to 18 minutes.
- Cool the cakes on the pan for 5 minutes then transfer them to a wire rack to cool completely.
- To make the filling: Cream the butter and shortening until fluffy. Add the powdered sugar and vanilla, blending well. Blend in the marshmallow cream.
- Using a plain tip, pipe a plump layer of filling on half of the cakes then sandwich them together. Roll the edges in American Almond® granulated natural or sliced natural almonds, if desired.