Skillet Beef Stroganoff

* 5c. sliced fresh mushrooms
* 1 lg. onion, sliced
* 1 Tbl. butter
* 1/3-1/2c. hot water
* 1 Tbl. prepared horseradish
* 1/2 tsp. salt
* 1/8 tsp. pepper
* 1/4 c. all-purpose flour
* 1 beef flank steak (1 1/4 lbs.), cut into 2" strips
* 1 c. (8 oz.) sour cream
* Cooked noodles

In lg. skillet, saute mushrooms & onion in butter until tender. Transfer to bowl, using slotted spoon; stir in the water, horseradish, salt & pepper. Set aside. Place flour in a lg. resealable plastic bag. Add beef, a few pieces at a time, & shake to coat. In same skillet, brown beef in batches. Return all beef to pan; top with mushroom mixture. Bring to a boil. Reduce heat; cover & simmer for 1 1/4 - 1 1/2 hours, or until beef is tender, stirring once. Remove from heat; stir in sour cream. Serve with noodles.