• For the Ganache
• There are a couple of different ways to do this:

  You could warm the heavy cream on the stove in a small sauce pot, or in a microwave safe bowl in the microwave, and pour it over the chocolate to melt it...

  You could combine the heavy cream and chocolate chips in a sauce pot on the stove, or in a microwave safe bowl in the microwave, and gently warm them together...melting the chocolate.
• I usually go the microwave route (fewer dishes)...

  Combine the heavy cream and chocolate chips in a medium microwave safe mixing bowl.
• Heat for 10-15 second intervals, stirring between intervals, until melted. Stir until smooth.
• Add the pinch of salt and vanilla, stir to combine.
• Set aside in the refrigerator until ready for use.

For the Cupcakes

• Preheat your oven to 350°F.
• Line muffin tin with baking wrappers. Set aside.
• In a large mixing bowl, combine all dry ingredients (flour, baking soda, sugar, salt and cocoa).
• Add mayonnaise, hot water, and vanilla and mix with a wooden spoon or electric mixer until thoroughly combined. Do not overmix.
• Evenly fill each muffin tin about ⅔ of the way full, or use a #20 disher.
• Bake cupcakes for 20-22min, or until a toothpick inserted into the center comes out clean.
• Allow cupcakes to cool for about 5min in the muffin tin before removing to a wire rack to cool completely (about 30min).

For the Frosting

• In a large mixing bowl, combine softened butter, powdered sugar, cocoa powder, milk, vanilla and salt.
• Beat with an electric mixer on low speed until well combined (about 2min).
• Once all ingredients are combined, mix on high speed for 1-2 minutes until the frosting is smooth and fluffy.
• Set aside until ready to use.

For Assembly

• Using a small paring knife, remove a small cone-shaped piece of cake from the center of each cupcake.

  Do NOT fully core the cupcake and remove all the way down to the wrapper – aim for the bottom of the hole you cut to be about halfway through the cupcake.

  Reserve the bits you cut out – you'll need these later.
• Using a spoon, scoop rounded balls of the chilled ganache large enough to fill the cored cupcake. Do not overfill.
• After filling each cupcake, pick up the piece of cake you cut out, squish it down a little to flatten it. Place it on top of the ganache filling.
• Frost cupcakes as desired.

  I used a piping bag and Ateco tip #287. Feel free to use whatever piping tip/technique you prefer, or use a palate knife and swirl the frosting on.