• Line two cupcake tins with liners and set aside.
• In a medium bowl, whisk together the oat flour, sugars, cocoa powder, baking soda, baking powder, and salt.
• In a large bowl, whisk together the coconut oil, eggs, yogurt, milk, and vanilla. Stir and whisk the dry ingredients into the wet ingredients and stir very well to combine. Stir in the coffee and stir until the batter is smooth and combined.
• Divide the batter evenly between the cups and preheat the oven to 350°F. Let batter rest while the oven heats, about 15 minutes.
• Place pans in the oven and bake for 30-35 minutes, checking at 30 minutes, until a toothpick in the center comes out clean and the sides are starting to pull away from the edges. Remove from oven and let cupcakes cool in the pans on a wire rack for 30 minutes, then turn out onto the rack to cool fully.
• Frost cupcakes with chocolate buttercream.

Chocolate Buttercream

• In a large bowl, cream the butter on medium speed. Add the powdered sugar, then the chocolate. Add milk 1 tablespoon at a time, keeping the mixer running, and beat until the frosting is smooth and fluffy.