2/3 cup all-purpose flour
2 1/2 tbsp unsweetened cocoa powder
3/4 tsp baking powder
1/4 tsp salt
3 oz bittersweet chocolate, chopped (I hate when they give you ounces! 3 oz is a little less than 1/2 cup. I used chocolate chips)
1/2 cup plus 3tbsp unsalted butter, cut into pieces
3/4 cup plus 2 tbsp sugar
3 large eggs, at room temperature
1 tsp vanilla extract
peanut butter chocolate reese cup filling (recipe follows)
peanut butter frosting (recipe follows)
6 miniature reese cups, for topping
Position a rack in the middle of the oven and preheat to 350 degrees F. Line a standard 12-cup muffin pan with paper or foil liners.
In a bowl, whisk together the flour, cocoa powder, baking powder, and salt. Place the chocolate and butter in a large heatproof bowl set over (but not touching) simmering water in a saucepan. Stir frequently until melted and smooth, about 5 minutes. Remove the bowl from the saucepan. Let the mixture cool to room temperature, 10-15 minutes.
Using a wooden spoon, stir the sugar into the chocolate mixture until combined. Stir in the eggs one at a time, beating until combined after each addition, and then beat in the vanilla. Gently fold in the flour mixture just until no traces of flour remain; do not overmix.
Divide the batter evenly among the prepared muffin cups, filling each about 3/4 full. Bake until a toothpick inserted into the center of a cupcake comes out clean, about 20-22 minutes. Let the cupcakes cool in the pan on a wire rack for 5 minutes. Transfer the cupcakes to the wire rack and let it cool completely, about 1 hour.
Peanut Butter Chocolate Reese Cup Filling
3/4 cup peanut butter
1/2 cup powdered sugar
1 tsp vanilla
1/2 cup chopped reese cups
about 1/4 cup heavy whipping cream
In a stand mixer, beat together peanut butter and vanilla on low. Slowly add the powdered sugar. once incorporated, add in the chopped reese cups. Then add heavy whipping cream until you reach desired creaminess.
Peanut Butter Frosting
1 stick unsalted butter, at room temperature
1/2 lb confectioners sugar, sifted
3/4 cups smooth peanut butter
1 tsp vanilla extract
2-4 tbsp heavy whipping cream
In a stand mixer, beat the butter until smooth, on low. Slowly add in confectioners sugar, once incorporated, beat on medium for about a minute. Add in the peanut butter until creamy, then add in vanilla. Once incorporated, add in whipping cream until frosting reaches desired consistency. Beat on medium for about a minute. (scrape down the sides throughout as needed so that all of the ingredients are getting incorporated equally into the mixture).
To fill cupcakes, I used the hollowing technique (I prefer using a Wiltons 230 tip for filling, but the chocolate in the filling will clog the tip). To hollow a cupcake use a pairing knife inserted at an angle and gently saw a circle. You want to end up with a cone-shaped piece about 1 1/2 inches in diameter and about 1 inch deep. typically you discard (or eat) the cones, but I cut off half of the bottom and placed them on top of the filling. To frost the cupcakes, I went around the outline of the cone and frosted as I normally would with a wilton 1 m tip.