For the Cupcakes:
- 1/2 cup Dutch-process cocoa powder
- 1/2 cup hot water
- 2 cups all-purpose flour
- 3/4 teaspoon baking soda
- 3/4 teaspoon baking powder
- 3/4 teaspoon coarse salt
- 16 tablespoons (2 sticks) unsalted butter
- 1½ cups sugar
- 2 large eggs, room temperature
- 1 egg yolk, room temperature
- 1¾ teaspoon vanilla extract
- 2/3 cup sour cream, at room temperature
For the Caramel Sauce:
- 1 cup (2 sticks) butter
- 1/2 teaspoon salt
- 2 cups packed dark brown sugar
- 1/2 cup milk
- 2 teaspoons vanilla extract
For the Filling:
- 12 fun-size Snickers bars, chopped
For the Caramel Frosting:
- 3 ½ to 4 cups powdered sugar
- 8 fun-size Snickers bars, chopped
- To make the cupcakes, preheat the oven to 350˚ F. Line muffin pan with paper liners.
In a two-cup glass measuring cup, whisk together the cocoa powder and hot water until smooth; set aside.
- In a medium bowl, whisk together the flour, baking soda, baking powder, and salt; set aside.
- In a medium saucepan over medium heat, combine the butter and the sugar, stirring occasionally until the butter is melted and mixture is combined. Remove from the heat and transfer to the bowl of a stand mixer fitted with a paddle attachment. Beat on medium-low speed until the mixture is cooled, about 4-5 minutes. Add eggs and egg yolk, one at a time, beating until each is incorporated, scraping down sides of bowl as needed. Mix in vanilla and cocoa mixture until incorporated. With the mixer on low speed add in the dry ingredients in two batches, alternating with the sour cream, beating just until combined.
- Fill the cupcake papers three-quarters full, making sure that the batter is divided evenly. Bake, rotating tins halfway through, until a toothpick inserted in centers comes out clean, 18-20 minutes. Allow the cupcakes to cool in the pan 5-10 minutes before transferring to a wire rack to cool completely.
- To make the filling, melt the butter in a heavy-bottomed saucepan over medium heat. Stir in the salt and brown sugar and heat the mixture to boiling, stirring constantly. Cook over low heat for 2 minutes, until the sugar is totally dissolved. Stir in the milk and return to a boil, stirring constantly. Remove the pan from the heat and stir in vanilla. Cool to lukewarm, about 30-40 minutes, stirring occasionally.
- Once cupcakes have cooled, use a paring knife or apple corer to cut out a small circle in the center of each cupcake.
- Remove the core and discard.
- To make the cupcake filling, in a medium bowl, combine the chopped Snickers and 1/4 cup of the cooled caramel sauce and mix to coat. Drop a spoonful of the filling mixture into each cupcake.
- Reserve three tablespoons of caramel sauce for drizzling over frosted cupcakes.
To make the frosting, transfer remaining caramel sauce to the bowl of a stand mixer fitted with the paddle attachment. Add the powdered sugar and beat on medium-high speed until until light and fluffy, about 3-4 minutes. Adjust consistency with a little more milk or powdered sugar, if necessary.Transfer the frosting to a pastry bag fitted with a decorative tip. Pipe a spiral of icing, beginning at the outer edge and working inward. Drizzle the frosted cupcakes with the three tablespoons of caramel sauce and garnish with chopped Snickers bars.
Source: adapted from Pass the Sushi and frosting from Sugar Duchess