I just made there for my office cookie exchange and they came out great. Couple of changes I made:

- added an extra egg to the brownie mix

- only cooked for 10 mins... tops...

- used aluminum foil cups that were liberally sprayed with PAM for baking

- took them out of the cupcake tins to cool on a rack immediately after removing from the oven

They came out perfect. Did not stick to the foil and were super moist.