After some research, I decided to give amylase enzyme a shot. I figured at such a high mash temp that I denatured the enzymes and ended up with a lot of unfermentable sugars (based partly on the fact that the iodine test detected no starches). I threw a teaspoon of of the powder into the carboy...
Okay, through a series of totally stupid things (which I am too embarrassed to mention), I ended up with an initial mash temperature of 164F on a 5-gal ESB batch. Target was 152F.
I immediately added 2 quarts of cold water, and got the temp down to 160F (I know, should have added ice...)...