1 medium onion, finely chopped
3 tablespoons butter
1 (8-ounce) package sliced portabella mushrooms
1 1/2 cups chicken or vegetable broth
1 1/2 cups sour cream
3 tablespoons flour
1/4 cup chopped flat leaf parsley
Salt and freshly ground black pepper

8 ounces medium egg noodles, cooked according to package directions
• In large, heavy skillet over low heat, sauté onion in butter until softened. Increase heat to medium-high, add mushrooms and continue to sauté until mushrooms begin to brown.
• Remove mushroom and onion mixture to bowl. Set aside.
In same skillet, over high heat, add broth to pan drippings, bring to a boil and reduce by 1/3. Lower heat to simmer and return mushroom/onion mixture to skillet.
• In a small bowl, combine sour cream and flour until smooth. Stir in sour cream mixture and continue stirring until sauce thickens, stir in parsley and season with salt and pepper.
Serve over hot cooked noodles.