I really liked the flavor the mussels got from the fresh thyme, complimented very nicely. I did substitute sour cream for the creme fraiche. I had all the ingredients to make it and then realized it was supposed to sit for day or so. I really didn't want the mussels to sit around so I used the sour cream. I still think it was a great recipe, so I am sure the creme fraiche would have been wonderful. Thanks Chia!!!