Preheat your oven to 350°F (175°C) and line your cupcake pans with paper liners.

In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt.

Add the eggs, milk, vegetable oil, and vanilla extract to the dry ingredients. Mix well until the batter is smooth.

Carefully stir in the boiling water, continuing to mix until the batter is well combined. The batter will be thin, but this is normal.

Pour the batter evenly into the cupcake liners, filling each about two-thirds full.

Bake in the preheated oven for 18-22 minutes or until a toothpick inserted into the center comes out clean. Allow the cupcakes to cool completely before moving on to the next step.

For the filling, beat the softened butter until creamy. Gradually add the powdered sugar, heavy cream, and vanilla extract, beating until smooth and fluffy.

Once the cupcakes are cooled, use a piping bag to fill each cupcake with the prepared filling.

For the ganache, heat the chocolate chips and heavy cream in a heatproof bowl over simmering water, stirring until smooth.

Dip the filled cupcakes into the ganache, allowing excess ganache to drip off.

Allow the ganache to set before serving, and enjoy your homemade Hostess Cupcakes!