Heat the oven to 350 F.
Season chicken with salt and pepper and rub with mustard.
In a Dutch oven or a big oven-proof skillet melt butter on a medium highheat. Add chicken and brown from both sides.
Transfer chicken to a plate.
Add shallot and onion to the same pot and saute for about 5 minutes.
Add chicken stock, scraping the brown bits off the bottom of the pot.
Add thyme and bay leave and bring a mixture to a boil.
Add Crème fraîche and transfer chicken back to the pot.
Braise in the oven for 50-60 minutes.
Garnish with parsley.
Serve immediately.