Homemade Hostess Cupcakes

Preheat the oven: Set your oven to 350°F (175°C) and line a 12-cup muffin tin with paper liners.
Prepare the cupcake batter: In a medium bowl, whisk together the flour, baking powder, baking soda, salt, and cocoa powder. Set aside.
In a separate large bowl, cream together the softened butter and sugar until light and fluffy, about 3-4 minutes. Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk, starting and ending with the dry ingredients. Mix until just combined.
Pour in the hot water and stir until the batter is smooth. The batter will be thin, but that’s normal.
Bake the cupcakes: Divide the batter evenly among the cupcake liners, filling each about 2/3 full. Bake for 18-20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Let the cupcakes cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.
Make the filling: In a medium bowl, beat together the marshmallow fluff, powdered sugar, softened butter, vanilla extract, and salt until smooth and fluffy. Transfer the filling to a piping bag or a zip-top bag with the tip cut off.
Prepare the ganache topping: In a small saucepan, heat the heavy cream over medium heat until it begins to simmer. Remove from heat and add the chopped chocolate and butter. Stir until smooth and glossy.
Assemble the cupcakes: Once the cupcakes are completely cool, use a small knife or cupcake corer to remove a small portion from the center of each cupcake. Fill the hole with the marshmallow filling, piping generously.
Dip the top of each filled cupcake into the chocolate ganache, covering the filling completely. Allow the ganache to set for a few minutes.
Finish the decoration: For the signature swirl on top, you can melt a little extra white frosting and pipe a swirl on top of the ganache, or you can use a tube of store-bought white icing to create the classic look.
Serving and Storage Tips: