I am doing some work in a volunteer kitchen and as part of our meals we provide cake that we bake in a big tray, we can only fit two on a rack in a commercial gas oven at a time. Full gastronorm trays I think they are called.
All our recipes call for a temperature of 180 degrees C (356 F) 40 mins - we rotate them in the oven after 20 mins.
The depth of the cake mixture prior to baking is about 5cm (2 inches) - not unusual.
The cakes are vegan - no egg or butter, we use oil. The lack of egg would affect binding which may be relevant. Essentially the recipes are vegan variations of a pound cake. (roughly by volume: 2 parts flour, 1 part each of oil, sugar, soy milk. Add in flavor, fruit etc. )
The problem is that by the time the cakes are cooked in the center, the outside is always burned. This seems to occur regardless of recipe to the point that our floor staff consider it normal to have to carve the burnt bits off the cake before serving. It works - just not a good solution...
Things I have thought of:
1) Use a lower temperature - but longer time. I don't want to go below 160 degrees or no maillard reaction (browning). But can't work out how much extra time I would need if I dropped the temperature by 10 or 20 degrees.
2) Chaining up the nameless idiot who keeps opening the oven door to see if the cakes are cooked yet. Said idiot swears that if he had an answer for number 1) then he would be able to restrain himself...
The tray size must have something to do with the problem, but I can't figure out what. I looked at the diffusion of heat - but it seems that the heat would be dominated by energy coming in from the top and bottom.
Possibly diffusion of steam?
Any other ideas?