1 small onion, diced
1 tbsp. butter
1 package "fondue" beef (ours was about 3/4 pound)
1 (12 ounce) package wide or extra-wide egg noodles
1 can condensed cream of mushroom soup
1 (7 ounce) can mushroom pieces, drained, optional

Place large pot of water on to boil for the noodles and prepare noodles per instructions. While waiting for the water to come to a boil, melt the butter in a large pan. Sauté the onion for a couple of minutes. Place beef in the skillet and brown on all sides (see note above). The fondue beef cooks quickly and takes about 5 to 10 minutes to cook. Add the can of mushroom soup and mix with the natural juices from the beef. Add the can of mushrooms and heat through. Drain the noodles and return to pot. Pour beef mixture over and toss.