Yesterday I tried making the 'cook in the oven, in an open baking tray' type
casserole that you get in Greece, and countries around that area.

They never use lids like we have on our casserole dishes that we have in the
U.K.. I found that some of the top layer of the veg get burnt black,
expecially the onions. Someone tells me that this charcoled burnt bits are
not healthy to eat at all.

Would i be better to use a lid? or maybe change my cooking heat and times.
At the moment I'm doing them for 1 hour 45 minutes at 160 degrees
centigrade. Thanks for any advice.