We noticed very little difference in our side - by - side test; the brownies in
a thick stoneware pan needed about 1 additional minute in the oven, but the brownies in the medium - gray (not dark) metal pan, and in glass, baked for the same amount of time.
:) I use a
stoneware bar
pan / jellyroll
pan so that it comes out about 1/2
thick or so, which is perfect for an open - faced sandwich, and also for PIZZA!