Preheat oven to 350 deg. Lay out 4 large sheets of foil, shiny side down & spray with no-stick spay. Place hamburger patty on each sheet. Place desired amount of potatoes & carrots on top of each patty.
Pace onion slice on top of potatoes/carrots & sprinkle with salt & pepper.
Wrap each packet completely & place on cookie sheet. Bake for 1to 11/2 hours or till hamburger is done & potatoes & carrots are tender. Unwrap & serve!