empty can of sprite, can of soup and soup packet into crockpot. Add onion and beef. Stir together, and cook on low for 4-5 hours. Stir contents, add frehs mushrooms and cook on high 1 hr longer. Sometimes I add a little crushed red pepper for some spice. Enjoy.
note: For convenience you can use canned mushrooms, they can go in at the beginning. Just cook about 7-8 hrs on low instead.