Preheat the oven to 375ºF.

In a large saucepan, melt the butter and black coffee over a low heat until fully combined.

Remove the coffee and butter mixture from the stove. Add the cocoa powder and dark chocolate chips to the saucepan and stir until fully incorporated.

Add brown sugar, salt, and vanilla and stir.

Add the whole eggs and egg yolks into the batter and whisk until they have fully incorporated into the mixture.

Add flour and baking powder. Whisk together until fully combined.

Fill each cupcake mold about 70% to avoid overflow when the cupcakes rise during the bake.

Bake the cupcakes for 20-22 minutes or until they reach 210º F in the center. The center of the cupcake should not be wobbly and a toothpick inserted should come out clean.

In a stand mixer, use the paddle attachment to cream the butter on medium speed until it reaches a smooth consistency, about 5 minutes. Be sure to pause halfway to scrape down the bowl to ensure no butter sticks to the sides or bottom of the mixing bowl.

Add the cookie butter and mix in on medium speed for about 3 minutes. Again, pause as needed to scrape down the bowl so that everything is able to mix together completely.

Slowly add the powdered sugar into the mixture. Start mixing on a low speed for 30 seconds, before switching to medium speed until the sugar is completely mixed in. The frosting will be a little bit stiff at this stage.

Add the heavy whipping cream and continue mixing on medium speed for another 2 minutes. Pause as needed to scrape the bowl for any mixture stuck to the sides and bottom of the bowl.

When the cupcakes are completely cooled, use a piping bag to pipe on the frosting on each cupcake and enjoy!