Don't think of Dijon mustard as just a spread; it's far more versatile. Here it rounds out the flavor of the onion gravy. Serve this dish with steamed zucchini, yellow squash, or carrots.
Heat oil in a large nonstick skillet over medium-high heat; add turkey. Sauté 6 minutes, or until browned. Remove turkey from skillet and set aside.
Add onion to skillet; saute 8 minutes. Add mushrooms; saute 3 minutes, or until tender. Add water, mustard, and broth; stir well. Return turkey to skillet and bring to a boil. Cover, reduce heat, and simmer 20 minutes.
Cook noodles in boiling water 8 minutes, or until tender. Drain and set aside.
Combine milk, flour, and pepper, stirring with a whisk. Add to turkey mixture. Simmer, stirring constantly, 2 minutes, or until thickened. Serve turkey and gravy over noodles; garnish with parsley, if desired.