Preheat oven to 350°F. Place cupcake liners in pans (I used three 12 cup pans). Blend cocoa, flour, baking soda and salt. Mix on medium speed butter and white sugar. Add brown sugar and beat until fluffy. Add eggs, one at a time. Mix in sour cream. Reduce speed of mixer to low and add flour mixture in small batches until incorporated into mix. Blend in buttermilk on low.

Fill cups about 3/4 full. Bake for 25-30 minutes. Place cupcake pans on wire rack and cool before removing from pans.

To make the frosting, heat the cream and corn syrup in a saucepan over medium heat. Place chocolate chip in large bowl. Bring cream to a simmer. Remove from heat and pour over chocolate chips. Let stand for a a couple of minutes to melt chocolate then blend together using a spatula until ganache forms and there are no lumps remaining. Spread 1-2 tsp on each cupcake. Adorn with sprinkles or other decorations before ganache sets.