1. In the bottom of your Crockpot on high, cook diced onions and ground beef for one hour, breaking up the meat every so often. If you have leftover roast beef, just cook the onions, and add chopped beef when they're done.
2. Add low-fat cream of mushroom soup and Worcestershire sauce to the meat mixture.
3. Layer the following: bag of mixed diced frozen veggies, mashed potatoes, and cheese. I use instant mashed potatoes to make things even easier, which I mix in a separate bowl.
4. Cover and cook on low for 6-7 hours, or high for 2-3 hours.
