Ingredients
Method
Step-by-Step
- Heat the oven to 350°F (175°C) and line a 12-cup muffin pan with paper liners.
- Whisk the flour, cocoa powder, baking soda, baking powder, and salt together in a medium bowl.
- Whisk the melted butter and sugar together. Beat in the eggs one at a time, then mix in the vanilla and sour cream.
- Add the dry ingredients and mix just until combined. Stir in the hot water or hot coffee; the batter will be fairly thin.
- Divide the batter among the liners, filling each about two-thirds full. Bake for 18-22 minutes, until the tops spring back lightly and a toothpick comes out with only a few moist crumbs.
- Cool the cupcakes in the pan for about 5 minutes, then transfer them to a rack and cool completely.
- Beat the softened butter until smooth. Add the marshmallow crème, powdered sugar, vanilla, and salt, then beat until fluffy; add cream or milk only if needed for consistency.
- Pipe the frosting onto the fully cooled cupcakes. Melt the chocolate chips with the optional oil or shortening, drizzle over the frosting, and finish with mini marshmallows and chocolate sprinkles.
Notes
Do not overmix after adding the flour, and cool the cupcakes completely before frosting. Store covered at room temperature for a short serving window or refrigerate for longer storage; allow chilled cupcakes to sit briefly before serving. Toast the mini marshmallows with a kitchen torch immediately before serving if desired.
