1. Heat oven to 350 degrees.
2. Prepare cupcake pans with liners.
3. In large bowl, stir together flour, sugar, cocoa, baking powder, baking soda, and salt. Add eggs, milk, oil, and vanilla extract. Beat on medium speed for 2 minutes.
4. Stir in boiling water. Batter will be very thin at this point.
5. Pour into cupcake liners. Fill about 2/3 full.
6. Bake about 22-25 minutes until toothpick comes out clean. Cool completely before adding the frosting on top.
7. For the frosting: Cream the butter first until light and fluffy. Add the confectioner sugar and cocoa powder and beat for another 1 to 2 minutes until combined. You may want to scrap down the bowl at this point. Then add the vanilla extract, espresso, and heavy cream. Then mix on high speed for 8 minutes until light and fluffy.
9. When cupcakes are cooled, then using a pastry bag and tip swirl the frosting on top. Decorate with sprinkles!