Preheat & Prepare: Preheat oven to 350°F (175°C). Line muffin tin with cupcake liners.
Dry Ingredients: In a bowl, mix flour, cocoa powder, baking soda, and salt.
Wet Ingredients: Beat together sugar, egg, milk, oil, and vanilla until smooth.
Combine: Gradually add dry ingredients to the wet mixture, alternating with hot water. Add espresso powder.
Bake: Fill each liner 2/3 full with batter and bake for 18-20 minutes. Cool completely.
Make Frosting: Beat softened butter, powdered sugar, brewed espresso, and vanilla until fluffy. Add cream for desired consistency.
Frost: Once cupcakes are cool, pipe the frosting onto each cupcake.