Brownies in the Crockpot

I got this recipe at A Year of Slow Cooking. the kids were so excited to smell sweet smells instead of savory from the crockpot.
I mixed up a batch of brownie mix according to the box. I then spayed 5 coffee mugs with cooking spray. I placed in the crockpot and cooked for 2 hours. I think 2 hour was a bit long next time i would check after and hour and then ever 15 minutes.