Preheat your oven to 350F. Line cupcake/muffin pan with paper liners. Set aside.
In large mixing bowl, combine flour, sugar, cocoa powder, espresso powder, salt, baking soda and baking powder. Whisk this flour mixture to combine.
To the flour mixture, directly add egg, vegetable oil, vanilla, and milk. Mix until well incorporated and mixture is a thick, glossy, dark brown paste.
Add boiling water to the mixture. (slowly)
Gently stir until the mixture transitions from a paste consistency to a thin liquid consistency.
Fill each cupcake liner approximately 3/4 full with batter. Divide any remaining batter into the 12 cupcake liners, making sure all have roughly the same amount of batter.
Bake cupcakes for ~25 minutes or until a toothpick inserted in the centre comes out clean.
Remove from the oven and allow to cool for 5 minutes in the cupcake/muffin pans and then transfer to a cooling rack to cool completely.