Prime Rib with Marsala Mushroom Sauce

Okay, this isn't my picture either (the picture is from Kraftfoods.com), but mine looked just as wonderful!  And it tasted AMAZING!  I served it for Christmas Dinner and it was an absolute hit.  The Marsala wine has 16 carbs for the entire recipe, but the recipe serves 16 people, so we are talking minimal sugars or starches per serving.    This may be my new Christmas Tradition!

Prime Rib with Marsala Mushroom Sauce

1 beef prime rib roast (7 lb.),

1/2 tsp.  coarse black pepper, divided

1/4 tsp. kosher salt

2 Tbsp.  butter

2 cups mixed sliced fresh mushrooms (baby bella, shiitake, oyster)

Xantham gum/ guar

2 Tbsp. GREY POUPON Dijon Mustard

1/4 tsp.  dried thyme leaves

1/4 tsp. ground sage

1-1/2 cups  25%-less-sodium beef broth

1/4 cup Marsala wine

HEAT oven to 325ºF.
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 145ºF. Let stand 10 min. (Temperature will rise to 160ºF).
MEANWHILE, melt butter in medium saucepan on medium heat. Add mushrooms; cook and stir 3 min. Stir in mustard, herbs and remaining pepper. Sprinkle a tsp. of xanthum gum/guar on top and stir.  Make sure there are no lumps.  When mixed, gradually stir in broth and wine; cook and stir on medium heat 4 min. or until thickened.
SERVE meat with sauce.