Gather all ingredients and equipment. Preheat oven to 325°F and line cupcake tin with liners.
In a large mixing bowl, whisk together the flour, cocoa powders, baking soda, baking powder, salt, and sugar. Add the eggs, mayonnaise, vanilla extract, and water to the dry ingredients and mix completely.
Using a piping bag fill the cupcake liners 3/4 full and bake for 22 minutes or until cake tester comes out clean. Allow the cupcakes to cool slightly and remove them from the pan. Cool completely,
Chocolate Mousse
Gather all ingredients and equipment.
In the bowl of stand mixer with the whip attachment whip together the egg yolks and powdered sugar until doubled in volume.
Bloom the gelatin in ice cold water. Heat the liqueur either on the stove or in the microwave and add the softened gelatin and have it melt into the liqueur.
In a microwave safe bowl melt the chocolate in 30 second bursts. Add the chocolate to the whipped egg yolks. Add the melted gelatin.
Fold in the whipped cream into the chocolate mixture by hand using a large whip. Refrigerate for 30 minutes
Assembly
Using an apple corer and hallow out the cupcakes.
Using a piping bag fitted with a large star tip fill the cupcakes with the chocolate mousse.