'Why would you remove the embers?'

Actually, you usually don't want to bake foods in a really high temperature. Meats are usually cooked best at 325-350F.

A fire burning in a hole for an hour or so should be, and stay, plenty warm enough to bake a chicken. If you wanted to bake some potatoes that way, you would probably want to raise the temp, so you could leave the embers in the bottom, cover with a layer of sand or soil, put your potatoes in and cover them.

A similar way of staying warm yourself (if you want to put in the effort), is to dig a fairly shallow trench as long as your body, build a good fire in it for a while, then refill it, and sleep on top. The heat should radiate up to you for most of the night. But I'm relatively sure that this wouldn't work in wet ground....

Sue