This recipe I found at Alpineberry, adapted from Tish Boyle's "The Good Cookie." It was very good!
Of course I am incapable of following recipes completely, I used a microwaved-from-frozen banana instead of a fresh banana (I have about a million frozen bananas in my freezer), and I also used less walnuts - I used about 1/2 a cup instead of a cup. The only reason for this is that I ran out of walnuts! I think it would have been even better with the full amount of walnuts. This cookie had a good amount of sweetness, and I think it could even stand alone without the chocolate.