Do not leave the lid on - 400 is about right. Olive oil and kosher salt is what I use and sometimes a drizzle of balsamic, depending on what I'm having with it.
The pan should also have very short sides, which is why I use a cookie sheet most of the time or my jellyroll pan.
thanks, elf. i hurried & took my lid off. i'd olive-oiled them with garlic, salt & pepper, then threw them in a roaster. i'm gonna transfer them to a cookie sheet. they smell delicious!