This is one of the cob homes build by architect and natural builder Ileana Mavrodin of Casa Verde in Banat, Romania. She, with a few others, are using natural materials in Romania to help people rediscover their local skills and community spirit.
Cob homes! And the website has more construction types for sustainable housing I'm loving these example of larger family sized cob homes that don't all look like hobbit holes.) I like that cob can be freeformed