• Preheat your oven to 350°F.

Make the Cookie Dough

• Make your cookie dough by combining the softened butter, granulated sugar, and brown sugar in a large mixing bowl.
• Use an electric hand mixer to cream the ingredients together for about 2 minutes, or until the sugar is completely dissolved.
• Add the egg and whisk again until the egg is fully incorporated. Reduce the speed of your mixer and gently whisk in the flour, cocoa powder, baking powder, and baking soda.

Shape and Bake the Cookies

• Divide your cookie dough into 12 evenly sized balls and flatten them slightly into thick disks.
• Arrange them on a greased cookie sheet.
• Bake the cookies for 11 minutes.
• When your cookies come out of the oven, use a spoon or small dish to create an indent in the center of each cookie.
• Let your cookies cool while you prepare the marshmallow filling and chocolate ganache.

Prepare the Filling and Ganache

• In one bowl, whisk together the marshmallow fluff and powdered sugar until homogenous.
• In another bowl, microwave the chocolate chips and heavy cream for 40 seconds.
• Stir the chocolate mixture until smooth and creamy.

Assemble the Ding Dong Cookies

• Add a spoonful of the marshmallow filling to each cookie indent and then top with a spoonful of ganache, ensuring the marshmallow fluff is completely covered.
• Serve immediately or wait about 45 minutes for your ganache to set.
• Optional: If you want to add an extra level of aesthetic to your cookies then you can use marshmallow fluff or a simple vanilla buttercream to create the classic white ding dong swirl on top of the ganache once it has set.