I got this recipe from About.com Southern Foods, it is the recipe of Diana Rattray. I have been making it a few years now, when ever I make Prime Rib, I usually also make this Sauce. I have no idea why it is called a sauce, it is actually a gravy that goes well with prime rib and Yorkshire pudding as well as Beef Wellington. It is thick and rich, and simmers slowly over low heat, and becomes nice and thick with the ham bits, and mushrooms, & onions. I made mine with Merlot wine but there are others that can be used also. All I know is my family has come to expect this with certain meat dishes
Add butter to a small sauce pan over medium low heat, then add chopped onions, green onions, garlic, & finely diced ham, and saute for about 5 minutes, or until onions are tender & transparent. Then add the mishrooms and cook an additional 3 minutes.
Then add the flour and stir, and cook for 4 minutes. Then add the beef broth & worcestershire sauce, thyme, wine. Allow to simmer over low heat, but stir occassionally to prevent scorching or sticking to sauce pan. about 45 minutes to 1 hour, taste, and adjust salt & pepper if needed.
Stir in parsley just before you are ready to serve, while still hot. Makes about 3 cups