Ecofriendly cooking with camping or rving

I'd rather not build a large fire and scorch the ground, scare the animals, and put smoke throughout the forest so
What are some ecofriendly ways of cooking when camping or rving? Is there a good way to contain a small fire that will cook food thoroughly? Without using propane or diesel, etc? I have seen solar ovens around but id say those are still quite expensive during the current era. Though solar price is gradually reducing over time. Can clay be used? In some sorta way? Ive seen clay refrigerators as well as terra cotta pots used to keep items cool. Tweet