These Chicken Thighs in a Creamy Mustard Sauce are delicious! This is the Barefoot Contessa's recipe that I changed a little because of my lack of ingredients she used. Specifically, she used crème fraiche, I have a hard time finding it so I substituted it with equal parts of heavy cream and sour cream. However, if you want more tang rather than fat content from the cream, just use sour cream! Works perfectly! You can actually make crème fraiche. It is whipping cream and buttermilk that you allow to sit on your counter for 8 to 24 hours. Not having time to do that I substituted. Next time I definitely will make this with crème fraiche to check the difference.