In a mixing bowl add the ground beef, egg, Dijon mustard, Worcestershire sauce, bread crumbs, and seasonings. Fold together until ingredients are well combined and then pinch off small amount of beef and roll to form the meatballs. (Meatballs should be 1 ½ inch in size)

Wisk water and gravy mix together and pour into crockpot. Add can of soup and stir together. Add in diced mushrooms and onions then place the meatballs in the mixture. Cover and cook on low for 5-6 hours or high for 3-4 hours. Serve & enjoy!