Preheat your oven to 175°C (350°F). Line the muffin tin with cupcake liners.

In a large bowl, whisk flour, sugar, cocoa powder, baking soda, baking powder, and salt.

Add egg, milk, oil, and vanilla extract. Beat on medium speed for 2 minutes. Stir in boiling water (batter will be thin).

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Bake for 18-22 minutes or until a toothpick inserted in the center comes out clean. Cool cupcakes in the tin for 5 minutes, then transfer to a cooling rack.

While cupcakes cool, prepare the cream filling: Beat butter until creamy. Add marshmallow fluff and mix until smooth. Beat in powdered sugar, milk, and vanilla until fluffy.

Once cupcakes are fully cooled, use a small knife or apple corer to cut a small hole in the center of each cupcake (do not cut through to the bottom). Save the tops.

Fill a piping bag with cream filling. Pipe filling into the center of each cupcake, then gently replace cupcake tops.

To make ganache, heat heavy cream and butter in a small saucepan over medium heat until just simmering. Pour over chocolate chips in a bowl. Let set for 2 minutes, then whisk until smooth. Allow to cool until slightly thickened.

Dip the tops of filled cupcakes into the ganache or spread using a spatula. Place on the rack until chocolate firms up.

For the white icing, whisk powdered sugar, milk, and vanilla in a bowl until smooth and pipeable. Transfer to a piping bag with a small round tip (or use a zip-top bag with the tip snipped off). Pipe a squiggly line across each cupcake to mimic the HoHos look.

Let icing set. Enjoy!