In a large mixing bowl, whisk the cake mix and pudding mix together. Add in the greek yogurt, applesauce, eggs, vanilla extract, and espresso water. Stir until well combined. Batter will be thick.

Using an ice cream scoop, or a 1/4 measuring cup, scoop the batter into the cupcake-lined muffin tin.

Bake in preheated oven for 18-22 minutes, or until a toothpick inserted in the center comes our with few crumbs attached. Allow cupcakes to cool in tin for 10 minutes before transferring to a wire rack to cool completely before filling.

Combine the hot water and salt in a small bowl and stir until dissolved. Let mixture cool.

In the bowl of a stand mixer, fitted with a paddle attachment, or with a hand mixer in a large bowl, beat together the marshmallow creme and the shortening until combined.

Add in the powdered sugar and vanilla and mix on high speed until fluffy--about 2 minutes.

Add the salt solution to the mixture and mix until combined.

Transfer filling to a pastry bag fitted with a tip.

Place the chocolate and the heavy cream in a microwave-safe bowl and heat in the microwave for one minute.

Remove bowl from microwave and stir until smooth.

In the bowl of a stand mixer, mix together the powdered sugar, butter, milk, and vanilla until light and fluffy.

Transfer icing to a pastry bag fitted with a round tip*

Once the cupcakes have cooled, push the tip of your pastry bag into the center of the cupcake and squeeze the filling out as you slowly pull the tip out. Smooth down any filling that is sticking out with a butter knife or offset spatula.

After all the cupcakes have been filled, dip the top of each cupcake one at a time into the ganache. Allow excess chocolate to drip off and place on a wire rack or baking sheet. Refrigerate dipped cupcakes for ten minutes, allowing to set. Remove cupcakes from refrigerator and dip a second time. Return cupcakes to the refrigerator, allowing the ganache to set up once again.

Once cupcakes have set, you are ready to pipe on the icing. Using your pastry bag, draw curls across the top of the cupcake.