Pork Medallions with Mushroom-Dill Sauce

1 1/2 pounds pork tenderloin, sliced into 6 to 8 pieces.
4 tablespoons butter
12 ounces sliced mushrooms
1 medium onion, chopped
salt and freshly ground pepper, to taste
1/2 cup dry white wine
1 cup beef broth, if canned, low salt
1 tablespoon flour
1/2 cup sour cream
1 teaspoon chopped fresh dill, or 1/2 tsp dried.

Flatten pork to about 1/2-inch thick with a meat mallet, if necessary.

In a large skillet over medium heat, melt 2 tablespoons of butter and cook the mushrooms for 6 to 8 minutes. Transfer to a bowl with a slotted spoon and set aside. Pour off liquid which accumulated in pan.

Over medium-high heat, melt the other 2 tablespoons of butter in the same skillet. Add the pork and cook 3 or 4 minutes on each side or until browned. Add onion and cook 3 to 4 minutes, or until softened but not browned. Sprinkle lightly with salt and pepper. Pour in the wine and half of the broth. Cover; lower heat to medium -low and cook for 15 minutes or until the meat is tender. Transfer pork to a serving dish and keep warm.

Stir flour into the skillet and blend with juices left. Over medium heat, stir in the rest of the broth and cook, stirring, until the sauce is smooth and thickened. Taste and adjust seasoning. Stir in sour cream and dill; add mushrooms and heat through (do not boil). Serve the sauce over the pork.

Serves 6 to 8