Preheat oven to 325 F. Place cupcake liners in muffin tin. Add flour, sugar, cocoa, baking powder, baking soda, salt and espresso powder in a large bowl. Combine until well-mixed.
Add milk, vegetable oil, egg and vanilla. Mix together on medium speed until wel-combined. Reduce speed and add boiling water. Beat on high for 1 minute.
Scoop batter into liners (2/3 - 3/4 full). Place in oven and bake 12-15 minutes or until toothpick come out clean. Let cool completely and frost.