For the cake batter: Preheat the oven to 350 degrees F. Line a standard cupcake or muffin pan with 12 cupcake liners.
Pour 1/2 cup water into a microwave-safe glass bowl and bring to a boil. In a large bowl, combine the flour, granulated sugar, cocoa powder, baking powder, baking soda and salt and whisk until combined. Add the milk, vegetable oil, vanilla, egg and boiling water and whisk to combine. Scrape down the sides of the bowl and continue to whisk until all the ingredients are fully incorporated.
Fill the liners three-quarters full with the batter and bake until cooked through, about 20 minutes. Cool the cupcakes completely before frosting.
For the vanilla bean cream filling: Combine the granulated sugar, salt and egg whites in the bowl of a heavy-duty stand mixer and set the bowl over a medium saucepan of gently simmering water. Whisk until the sugar is dissolved and the mixture is frothy and smooth and registers 160 degrees F on a candy thermometer, about 5 minutes.
Transfer the bowl to the mixer and beat on high speed with a whisk attachment until the mixture has cooled completely and formed stiff and glossy peaks, about 7 minutes. With the mixer running, add the butter one piece at a time. Continue beating until all of the butter is incorporated and the mixture looks smooth. Separate out 1 cup of the buttercream and add the vanilla bean paste. Set aside for filling the cupcakes.
For the espresso buttercream: Add the confectioners' sugar and espresso to the remaining buttercream and beat on low speed with a paddle attachment until smooth.
For the chocolate shell: In small microwave-safe bowl, combine the chocolate and oil. Microwave on medium heat for 1 1/2 minutes, stirring halfway through. Cool completely before using.
To assemble: Cut out a hole in each cupcake and fill with some vanilla bean cream filling. Frost each cupcake with some espresso buttercream. Refrigerate for about 15 minutes, and then dip half of each cupcake in the chocolate shell. Refrigerate again for about 10 minutes.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.