Oh, Giada, can you do no wrong?
I can't even remember the last time I had chicken Marsala, but this is certainly the best iteration of it that I have ever had. Although, when we were in high school, my brother went through a phase when he was obsessed with chicken Marsala and made it all the time. (At least I think it was high school; I could be remembering this incorrectly.) His version of it was terrific as well.
This recipe is from Giada's cookbook, Giada's Family Dinners, which I recently bought on Gilt for super-cheap. (If you are not a member of Gilt, let me know and I will send you an invitation. It is one of the most amazing things ever created. Really great products for unbelievably low prices. Especially if you are an obsessive shopper like I am!) Of course, you can also find this recipe on foodnetwork.com. The mustard and mascarpone work really well with the Marsala and the browned mushrooms. (A note on the mushrooms, which most of you probably know already: cremini mushrooms are also called "baby bella" or "baby portobello".)
A note on the serving size: I used just over a pound of chicken, and a half pound of pappardelle, but the full amount of all the other ingredients (I like a lot of sauce) and it made 4 servings.