Combine Creme Fraiche, Mustard in a bowl and whisk until combined.

Pour over the chicken and marinade for 30 minutes or overnight.

Heat the oil in a non stick pan.

Add the chicken to the pan and cook for 5 minutes over a medium high heat.

Turn over, reduce the heat to medium low, cover with a lid, and cook for 20-25 minutes, rearranging every 5-10 minutes.