Broccolini with Filet Mignon and Balsamic Mushroom Sauce

This sauce is so good! My husband says it's the best thing I have ever made! Makes 4 servings.

1/2 pound shiitake mushrooms, sliced (use half crimini or white if desired)
5 tablespoons butter or margarine
1/2 cup dry white wine
1 1/2 cups beef broth
1 teaspoon thyme, chopped
1 teaspoon balsamic vinegar
2 teaspoons flour
1/2 teaspoon black pepper, medium ground
4 (6 ounce) filet mignon steaks
2 (8 ounce) bunches Mann's Broccolini®

For sauce, saute mushrooms over high heat in 2 tablespoons of butter until limp. Add wine to pan and scrape up any pan drippings Add broth, thyme, vinegar, and pepper. Bring to boil. Melt remaining 3 tablespoons butter and blend with flour. Stir flour/butter mixture into sauce and cook, stirring until thickened. Keep warm.
Grill or broil steaks as desired. Drop Mann's Broccolini into saucepan of boiling water. Drain after 3 minutes. Serve Broccolini and steak with sauce, accompanying with potatoes au gratin, if you like. Makes 2 1/3 cups sauce.