1 cup all-purpose flour
1/2 teaspoon baking soda
1/4 teaspoon salt
1/2 cup boiling water
1/2 cup unsweetened cocoa powder
1/4 cup semisweet chocolate chips
1/2 cup granulated sugar
1/3 cup brown sugar
1/2 cup coconut oil
2 large eggs
1 teaspoon vanilla extract
1/2 cup sour cream
filling:
3 tablespoon water
1 teaspoon unflavored gelatin
4 tablespoons (1/2 a stick) unsalted butter, room temperature
pinch of salt
1 teaspoon vanilla extract
7 ounces marshmallow fluff creme (1 and 1/4 cups)
chocolate ganache:
1/2 tablespoon butter
1/2 tablespoon light corn syrup
4 ounces semisweet chocolate, chopped (or 1/2 cup chips)
1/3 cup heavy cream
Preheat oven to 325 degrees. Grease and lightly flour a 12-cup muffin tin. Combine flour, baking soda, and salt in a medium bowl, set aside. In a separate large bowl, whisk together water, cocoa powder, and chocolate chips together until smooth. Add sugar, oil, eggs, and vanilla and mix until combined. Whisk in flour mixture alternating with sour cream (beginning and ending with flour), until incorporated. Using an ice cream scoop, divide batter evenly among prepared cups. Bake 18-22 minutes, until a toothpick inserted in the center comes out almost clean. Cool cupcakes in tin for 10 minutes, then turn out onto a wire rack to cool completely.
While cupcakes are cooling, make the filling: Combine water and gelatin in a large bowl and let sit until gel softens, about 5 minutes. Then microwave for 30 seconds until mixture is bubbling around the edges and gelatin dissolves. When slightly cooled, whisk in marshmallow creme until smooth. Refrigerate filling until set, 30 minutes. Transfer 1/3 cup marshmallow mixture to pastry bag fitted with a small plain tip.
To make the ganache, add heavy cream and butter to a large microwave safe bowl and heat for 2 minutes in the microwave until butter is completely melted. Add chopped chocolate and stir until chocolate melts and is smooth. Stir in corn syrup and allow to cool to room temperature, about 10 minutes.
When cupcakes are cool, insert a paring knife about 1/4-inch away from the edge of each cupcake at an angle. Proceed to cut a circular cone shape out of each cupcake. Cut the point off each cone to create a flat lid. Using a small spoon, fill each cupcake with marshmallow filling, then add the lid. Lightly frost with chocolate ganache. Let set, then pipe swirls on top with reserved marshmallow filling.