Abe of the Wild Harvests blog visited the Food Sovereignty Project at the Muckleshoot Indian College to give a presentation on earthen pit oven cooking. From his post:

By 11:30, the rocks were nearly red hot and we scooped the unburned coals from the cooking pit and packed in our root vegetables. Salal, which has amazingly fireproof leaves, was placed directly on the hot rocks and then covered with a mattress of sword ferns. We placed carrots, onions, yams, and potatoes on top of the sword ferns, and then placed more sword ferns on top. Then we poured water over the entire thing and quickly covered it with burlap and a couple inches of soil to seal in the steam.

You can read an earlier post and watch a video on the Food Sovereignty project here.