Preheat the oven to 350°F (177°C). Line a 12-count cupcake pan with cupcake liners. Set aside.

Melt the butter and chocolate together in the microwave. Microwave in 30 second increments, stirring between each time. You may also melt the butter and chocolate over low heat on the stovetop. Stir until smooth and set aside to slightly cool.

In a medium sized bowl, toss the cocoa powder, flour, baking soda, baking powder, and salt together until thoroughly combined. Set aside. In a large bowl, whisk the eggs, sugar, brown sugar, and vanilla together until smooth. Add the cooled butter/chocolate and whisk until smooth. Add half of the flour mixture, then half of the buttermilk. Repeat until everything is added. Stir until *just* combined; do not overmix. The batter will be very thick like pudding.

Fill the cupcake liners 2/3 of the way full with batter. Bake for 18 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting.

Sift together the confectioners’ sugar and cocoa powder to assure there are no lumps. Set aside. With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy—about 2 minutes. Gradually add the sifted sugar/cocoa powder alternately with the heavy cream and vanilla. Beat on low speed after each addition. Once all added, beat on high speed until creamy and combined for at least 2 minutes. Add a pinch of salt if frosting is too sweet.

Frost cooled cupcakes and top with chocolate chips as desired. Cupcakes stay fresh at room temperature in an airtight container for up to 4 days. Store covered in the refrigerator is desired for up to 1 week.