Don't you love it when a few ordinary ingredients somehow combine to create a superb flavor far beyond the ( expected) sum of its parts ? The recipe was published decades ago in Bon Appetit . I've made it a few zillion times for family and for catering clients. It's inexpensive, very fast, and addictively good.
Two caveats: if not served immediately, your noodles (even more than rice) will absorb all the rich sauce if left to languish very long, so don't mix them until the last minute. If you anticipate that they'll end up sitting a few minutes before eating, double the sauce ingredients to have extra. And the second caution is not to think you can skip or substitute something else for the Dijon. Now and then there is a sole ingredient responsible for a flavor meld, and this is the role of the Dijon. You won't identify the flavor profile as being mustard-y, just delicious!
Cut 5 skinless chicken breasts in 1" pieces and brown lightly in batches in 2 TB butter for about 5 minutes, removing to another dish and keep warm if you're serving soon. Don't crowd the pan, or you'll steam the chicken. To the pan, add 8 oz. sliced fresh mushrooms and 1 medium onion, sliced. Cook until light brown, 6-8 minutes and then add to the dish with the chicken. These steps can be done ahead. Bring the chicken, onion and mushrooms to room temperature again, and then warm briefly before proceeding.
Serve to 4-6 people over rice or buttered noodles, and sprinkle with chopped parsley for a pretty touch of color.
