I regularly put (decaf) coffee in my hot chocolate drinks (and vice versa) but altogether in a cookie cake? Sounds like heaven to me. Joy Cho kindly published a recipe for Eater:
Think of this easy recipe as a edgier, caffeine-spiked version of your classic chocolate chip cookie. Brown a stick of butter until it smells nutty and toasty, then whisk in brown sugar, granulated sugar, and a tablespoon of instant espresso powder. Mix in an egg and a splash of vanilla extract, then add the dry ingredients. Chop up a bar of good-quality dark chocolate (chunks over chips, forever and always) and a generous handful of chocolate-covered espresso beans (they’re easier to find than you may think) and fold those in to finish. Spread the dough into a cake pan and voilà, have a wonderfully decadent, espresso-laced cookie cake ready to serve (or savor on your own) in under half an hour.
The double-dose of espresso does double duty here: the espresso powder infuses the cookie with subtle coffee notes and tempers its sweetness, while the chocolate-covered espresso beans provide pops of concentrated flavor. Taken together, they’re a reminder that just a few ingredients can go a long way in transforming a classic into something new and unexpected. Consider sending a cookie care package their way if you’re looking to surprise someone with a thoughtful gesture.
There’s a reason the Cookie Monster is my favourite character from Sesame Street.
Chocolate related: Hot chocolate with added spice and emerald marine chocolate mint tart