Place meat in shallow pan; sprinkle with 1/4 tsp. pepper and salt.
Bake 2 to 2-1/2 hours or until internal temperature of meat reaches 145F.
Let stand 10 min. (Temperature will rise to 160F).
Meanwhile, melt butter in medium saucepan on medium heat.
Add mushrooms; cook and stir 3 min. Stir in flour, mustard, herbs and remaining pepper. Gradually stir in broth and wine; cook and stir on medium heat 4 min. or until thickened.