Slow-cooker Beef Stroganoff
3 lbs. beef round steak 1/2 cup flour 2 teaspoon salt 1/8 teaspoon pepper 1/2 teaspoon dry mustard 2 medium onions, thinly sliced and separated into rings 2 (4 oz.) cans sliced mushrooms, drained or 1/2 lb. mushrooms, sliced 1 (10 1/2 oz.) can condensed beef broth or equivalent amount of beef stock 1/4 cup [...]
