Preheat the oven to 350 degrees F. Line 2 regular size cupcake pans with cupcake liners.

In a large bowl using an electric mixer on low speed, combine the sugar, flour, cocoa, baking powder, baking soda, and salt. Add the eggs, half-and-half, oil, and vanilla and beat on medium speed for 2 minutes. Stir in the boiling water until fully combined.

Fill the cupcake liners three-quarters full with batter and bake until the cupcakes spring back when touched with your finger, 10 to 15. Let cool in the pans for a few minutes, and then remove to a wire rack to cool completely.

Dip the tops of the cupcakes in Chocolate Ganache. Pipe Marshmallow Frosting onto the cupcakes using a pastry bag and your favorite tip.

In a medium saucepan, bring the whipping cream to a simmer. Take off the heat and add the chocolate. Let the mixture sit for 5 minutes. Whisk the mixture until smooth and creamy.

Place egg whites, sugar and cream of tartar in a heat-safe bowl over a saucepan with boiling water. Whisk constantly over the heat for 1 to 3 minutes. Once the sugar has dissolved, remove from the heat and beat with an electric mixer on high until stiff peaks have formed, 5 to 7 minutes. Stir in the vanilla extract.