We got quite a few red bell peppers from the garden this summer, but not very many of them were without blemishes or insect damage of one kind or another. We had to cut them up and trim then before we could cook them into ratatouille or poulet basquaise — to name two examples.
Yesterday I noticed three nice, bright red poivrons that had been ripening out on the terrace among a couple of dozen tomatoes. They looked like good candidates for oven-roasting. I haven't cut them open and de-seeded them yet, so I don't know how thick the flesh will be. Some peppers seem to be all skin with little "meat".
Peppers roasted in a 400ºF (200ºC) oven for about 30 minutes sort of shrivel up and collapse. I poke some holes in them before putting them in to roast because I don't want them to burst when the air inside them expands. The peppers' skin starts to darken and blister.
When they come out of the oven, they need to be cooled in a paper bag or in a covered dish so that steaming from their residual heat will loosen the skins even more. I just put them in a dish and cover it tightly with plastic wrap. When they're cool they are ready to be skinned and seeded. Then they are delicious just dressed with olive oil, salt and pepper, and maybe a few drops of vinegar. Balsamic is especially good.