In a bowl, whisk together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.

In another bowl, beat the softened butter and granulated sugar until creamy.

Add the egg and egg yolk, then mix until well combined.

Add the vanilla extract and mix until smooth.

Gradually add the dry ingredients to the wet mixture and mix until combined.

Add the buttermilk and mix until a smooth batter forms.

Add the hot brewed coffee and mix until evenly incorporated.

Divide the batter evenly among the prepared cupcake liners.

Bake at 350°F (175°C) for 17–22 minutes, or until a toothpick inserted into the center comes out clean.

Remove from the oven and allow the cupcakes to cool completely.

Using a piping tip or small cutter, make a hole in the center of each cupcake.

For the edible cookie dough, mix the softened butter, granulated sugar, brown sugar, milk, salt, flour, and mini chocolate chips until a smooth dough forms.

Fill the center of each cupcake with the edible cookie dough.

For the vanilla buttercream, beat the softened butter until creamy, then add the powdered sugar, vanilla extract, and salt and beat until light and fluffy.

Pipe the vanilla buttercream over the filled cupcakes.

Top with mini chocolate chips, then serve and enjoy.