Preheat oven to 350 F
Bring your water to a boil in the small pot. Turn off once it's bubbling, so none of it evaporates.
Mix flour, sugar, cocoa, baking powder, baking soda, salt, and instant espresso powder in the large bowl. Mix until combined.
Add milk, oil, egg, and vanilla to the dry ingredients. Mix until combined, and keep stirring an extra minute or so to incorporate air into the mixture.
Carefully pour in the boiling water, and stir until combined. Be careful with this so you don't burn yourself.
Evenly distribute the batter between 2 bundt pans.
Bake for about 20-25 minutes, or until you can insert a toothpick and it comes out clean.
Enjoy warm or let cool! Decorate as you wish!