1) Preheat oven to 350 degrees F. In a medium bowl, whisk together flour with cocoa powder, baking soda, baking powder, and salt.
2) In a stand mixer with the paddle attachment (or with a hand mixer) beat together butter and brown sugar until light and fluffy. Then beat in egg and vanilla extract.
3) Slowly add the dry ingredients and buttermilk in alternating batches until the batter is mixed together smoothly. Optionally, add black food coloring to make the color darker!
4) Scoop out heaping spoonfuls of the batter onto two baking sheets lined with parchment paper. You should get 24 small cakes.
5) Bake cakes at 350 degrees for 16 minutes, rotating pans halfway through to ensure even cooking. Let cakes cool when they come out of the oven.
1) Beat together softened butter and powdered sugar in a stand mixer with paddle attachment (or with hand mixer) until it’s light and fluffy. Add vanilla and marshmallow fluff. Continue to mix until combined.
2) Add orange food coloring if you want (or a combination of yellow and red).
Make whoopie pies by spreading a generous portion of filling onto half of the cakes. Sandwich with second half and roll the outer edges of the whoopie pies in orange and red decorating sugars or nonpareils.
Store whoopie pies in an airtight container in the fridge for 3-4 days.