This is a truly extraordinary video. The text provided by the film maker  identifies the bread as follows:

This is on the edge of the Sahara Desert near Zagora, Morocco. The locals make bread by placing the dough on heated rocks and cooking the top with palm fronds. The dough is then buried in the heated sand and left to bake thoroughly. Later it will be dug up, brushed off, and eaten warm.

Note that the bread is set over a very clear bed of hot rocks that seem not to have ash on them so they were presumably brushed off. The rink of rocks is perfect. Burning palm fronds are then being held over the breads to both illuminate the scene, but I also think to help set the to crust before the hot sand is poured over them.

The video does not offer the source of that hot sand. If you know something about this please post a comment. Thank you.

https://youtu.be/eCxCNGX-s3s