DentonDoc wrote on Jul 29^th, 2009 at 2:37am:

A little less fire and more cooking time would be my guess.   dd

I'll second that thought.  

FWIW, for the first time in many years I dusted off the ol' reflector oven for the houseboat trip I recently took to Voyageurs.  I cooked up a batch of cornbread (similar consistency batter as your brownies, I'd guess).  I turned the pan a couple times early in the process, then let it go a bit longer between turns the rest of the way.

The more soupy the batter, the more you need to turn the pan.  Also watch the heat level and keep feeding the fire gradually to keep it fairly even.  If the edges are setting up too fast, even with frequent turning, then back off the fire a bit.

Anyway, the cornbread turned out well.  The kids thought it was really cool to cook in front of a fire like that.  I was pleased to see that reflector cooking is a bit like riding a bike.  Get the knack and you are good to go, even a decade or more later...