Bake Farm Rich Potato Skins according to package directions and keep warm.
In a large skillet, over medium high heat, saute the ground beef and diced onion together until the ground beef is cooked through and onions are translucent. Stir in beef stock. Add cheese and cover the pan to melt the cheese. Stir mixture together.
Spoon cheeseburger mixture on top of each Potato Skin and top with shredded lettuce and tomato slices.