Preheat the oven to 350 degrees.
Line a mini cupcake pan with paper wrappers and set aside. I used a 2 1/4" cupcake pan from Ikea. This recipe makes approximately 32 mini cupcakes, so you may have to work in batches.
In a large bowl, whisk together the white granulated sugar, brown sugar, flour, cocoa powder, baking soda, baking powder, and salt.
Add the egg yolks, buttermilk, coffee, oil, almond extract, and vanilla extract and mix with an electric mixer until thoroughly combined.
Stir in the sour cream.
Fill each cupcake wrapper 3/4 full with batter and bake 15 minutes.
Allow to cool before frosting.