Picture coming soon.
Sadly, I don't have my camera here tonight which really is a shame because I know that this will not look nearly as appetizing cold or reheated. Source. (SR has been a favorite source of mine for awhile. Lives up to its name quite well.)
I actually moved from pan to baking dish since I didn't have a cast-iron skillet large enough for this (someday, I'll have a set of iron cookware.). I interpreted thinly sliced onions to mean Frenched onions. (They smell better in the pan this way.) I'm still working on a good way to French onions quickly. Standing them up and holding them only works about halfway through. Sauteed onions in the pan a bit before adding chicken thighs, peppered, salted, basil'd, and oregano'd before flipping the meat-side down. I cut the garlic this time since I've been eating a lot of garlic lately (in lentils and rice [which was mildly disastrous] and in Korean food) and the white wine since I didn't have any. After a good sear, I transferred them to a baking dish (where I had already moved some onions for a bed) and added tomatoes. I subbed, in place of plum tomatoes, canned pear tomatoes in bay leaves. Covered with the remainder of onions and made sure the tomatoes were well distributed.
At 350 for 40 minutes with foil (which may or may not have been necessary), then another 20 at 400 (because I was getting annoyed). I let it sit in the oven for another 10 or 15 with everything off to let it cool to edible temperatures. I was concerned because it looked a little too reduced at this point, but it was just the liquid that had settled instead of boiling like mad.
The meat was nearly falling off the bone but not quite (which is exactly right). The Frenched and sauteed onions really made a difference. A different tomato and some more spices would have helped, but overall, it turned out very well. Would go well with yellow rice or plain, sliced potatoes and a glass of red.
Addendum.
Reheated for a late dinner tonight. It looked way better fresh out of the oven.