In a bowl combine chicken slivers, 1 tablespoon mustard, 1 clove minced garlic and salt/pepper. Let the flavors marinate while you prepare the other ingredients.

Heat pan over medium heat and add 1 tablespoon olive oil. Add mushrooms and cook until lightly browned (do this in batches if pan too small). When mushrooms cooked add garlic and cook until just aromatic. Remove mushrooms and garlic from pan.

To the same pan add remaining olive oil and chicken slivers. Cook until browned on each side and cooked through. Remove from pan.

To the same pan add white wine, wait for it to reduce by half and the add creme fraiche and mustard. Mix and cook until sauce is thick enough to coat the back of a spoon. Add mushrooms and chicken back to the pan, reduce heat to low and add the cheese. Mix. Add some of the pasta water to the pan if the sauce is too thick.

Serve over pasta.