In a large bowl, whisk together the granulated sugar, brown sugar, flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

In a small bowl, whisk together the eggs, vegetable oil, and vanilla extract until completely combined. Pour the wet ingredients into the dry ingredients, add the coffee, and whisk or stir the batter until everything is combined. Fold in the chocolate chips.

Spoon batter evenly into the cupcake liners filling ½ to ⅔ of the way full (I like to use an ice cream scoop with a trigger-- one scoop full). Bake for 18-19 minutes or until a toothpick inserted in the center comes out clean. Allow to cool in the pan for a few minutes, then transfer to a wire cooling rack to cool completely.

In a large bowl with a handheld mixer, or a stand mixer fitted with the paddle attachment, beat the butter on medium speed until creamy, about 2 minutes.

With the mixer on low, add in the powdered sugar, peppermint extract, and milk or cream. Add the food coloring, increase mixer speed to medium, and beat until completely smooth, about 3 minutes. If frosting is too stiff, add more milk. If it is too thin, add more powdered sugar.

Stir in the mini chocolate chips with a spatula.