In a large bowl, combine flour, sugar, cocoa, baking powder, baking soda, espresso powder and salt. Stir to combine.
Add eggs, sour cream, melted butter and vanilla to the dry ingredients.
With an electric mixer, begin mixing on low speed and increase to medium speed until combined. To ensure tender cupcakes, do not overmix. Turn off mixer.
Carefully add boiling water. Mix on high speed for 1 minute.
Evenly fill each liner 1/2 to 3/4 full with batter. We like to use an ice cream scoop or a 1/4 cup dry ingredient measuring cup (filled about 3/4).
Bake for 20 minutes. Insert a toothpick and when just clean, remove from the oven. Allow to cool on a cooling rack. Do not overbake.
Ganache
While the cupcakes are cooling, with a double boiler bring an inch of water to a simmer. Alternately, bring an inch of water to a simmer in medium sauce pan. Cover sauce pan with a metal or glass bowl. Add chocolate chips and heavy cream. Stir occasionaly until warm, melted and velvety.