In a cup or jug, whisk the hot water with the espresso powder until dissolved.

In a large bowl, whisk together eggs, oil, sour cream, espresso mixture, brown sugar, and granulated sugar until smooth.

Add flour, cocoa powder, salt, baking soda, and baking powder. Stir until almost smooth.

Fold in the chocolate chips.

Cover and let the batter rest for 30–60 minutes to improve texture and rise.

Preheat oven to 425°F (220°C). Line a muffin pan, filling every other cavity for better rise.

Fill each cup slightly over ¾ full.

Bake at 425°F for 5 minutes, then reduce temperature to 350°F (175°C) and bake for 15–18 minutes.

Cool in the pan for 10 minutes before transferring to a wire rack to cool completely. For a bakery finish, press extra chocolate chips on top immediately after baking.