Simple and quick recipe! I would add more expresso powder next time though. I didn't have raising powder so I added 1/4 teaspoon of soda bicarbonate and 1/2 tsp of apple cider vinegar and it worked brilliantly.
Edit : I had a poor quality espresso powder so I doubled the amount and it was perfect!
Edit 2: did this recipe again and swapped chickpea flour for green lentil flour cause I didn't have any chickpea flour left, and it worked great again!