Preheat oven to 375° F (190° C).

Prepare the chocolate cupcake batter: In the bowl of a stand mixer with a paddle attachment, cream softened butter and sugar together until light and fluffy. Add eggs, one at a time, beating after each addition until just combined. Beat in vanilla and Nutella. In a separate bowl, combine together the flour, cocoa powder, baking soda, and salt. Beat in flour mixture at low speed into the creamed butter-sugar mixture, alternating with buttermilk and water, beating well after each addition.

Fill paper-lined muffin cups two-thirds full. Bake for about 15-18 minutes or until a toothpick inserted in center comes out clean. Place pans on a wire rack and let cupcakes cool completely.

For the marshmallow frosting: In the bowl of an electric mixer, beat the softened butter until smooth. Beat in both the vanilla and marshmallow creme. With the mixer on low speed, gradually beat in the sifted powdered sugar and then the salt, scraping down the sides of the bowl as needed. Add the cream and beat to combine. Then, on high speed, beat frosting until it is light and fluffy (approximately 3-5 minutes). Add more cream or powdered sugar if necessary to get the right piping consistency.

Open a medium hole (starting from the top to the middle -- don't go all the way to the bottom) in the center of each cupcake and fill/pipe in a good amount of marshmallow frosting. Using a star tip or other of your preference, pipe marshmallow frosting on top and decorate FROZEN cupcakes as desired. I used edible sterling pearl blue bell dust on top of the snowflakes, as well as metallic dragees on top of the frosting. WATCH this SHORT VIDEO to learn how to mold the gumpaste/fondant snowflakes.