for the cupcakes
3 ounces bittersweet chocolate, finely chopped
1/3 cup Dutch-processed cocoa
3/4 cup hot, strong-brewed coffee
1 cup all purpose flour
3/4 cup granulated sugar
1/2 teaspoon table salt
1/2 teaspoon baking soda
6 tablespoons vegetable oil
2 large eggs
2 teaspoons white vinegar
1 teaspoon vanilla extract
16 Oreo halves, with cream filling attached
1 cup (2 sticks) unsalted butter, softened to room temperature
6 to 8 cups confectioners’ sugar
1/2 cup milk
2 teaspoons pure vanilla extract
6 tablespoons Oreo cookies, finely crushed
16 Oreos for the top of each cupcake or 48 of the mini-oreos, and put a couple on each to garnish
Preheat oven to 350F and line a muffin pan with cupcake liners. Twist Oreos in half and set aside the extra cookies for later. Place the side with cream filling in the bottom of each cupcake liner, cream-side facing up.
Place chocolate and cocoa in a medium bowl and pour the hot coffee over the mixture. Whisk until smooth and transfer to the refrigerator to cool completely, 20-30 minutes. Whisk flour, sugar, salt, and baking soda together in a medium bowl; set aside. Whisk oil, eggs, vanilla, and vinegar into the cooled chocolate mixture until smooth. Add flour mixture and whisk until batter is smooth.
Divide batter evenly among muffin pan cups, filling each 3/4 full. Bake until cupcakes are set and firm to the touch, 17-20 minutes. Allow to cool in pans 10 minutes, then transfer to a wire rack to cool completely before frosting.
In the bowl of an electric mixer fitted with the paddle attachment, combine butter, 4 cups sugar, milk, and vanilla. Beat on medium speed until smooth and creamy, 3 to 5 minutes. Add in the crush oreo cookies. Gradually add remaining sugar, 1 cup at a time, beating for about 2 minutes after each addition, until icing reaches desired consistency; you may not need to add all the sugar.
Scoop the mixture into a pastry bag and pipe on top of the cupcakes. Garnish with Oreo cookies.