Pre-heat oven to 350 degrees
First rip off 6 pieces of foil that are about 16-17 inches long and set aside. In a mixing bowl add ground beef, ranch packet, onion soup mix, and BBQ sauce; use hands to mix well and form 6 patties. On a clean surface cut potato and onion into thick slices, you will need 2-3 slices of each per hamburger boat. Salt and pepper the onions and potatoes ( I use my hands to rub the salt and pepper all over them). Now take a sheet of foil and lay down 2-3 potatoes side by side but slightly overlapping in the middle, lay hamburger patty on top of the potatoes, lay onions on top of the hamburger patty ( I give it a little squish into the patty), add mushrooms on top of the onion ( if desired) and drizzle the top with a little more BBQ sauce ( about 1 Tbsp.). To make the foil pack, bring longer ends together and fold down, then fold each side in just till it meets the hamburger boat. Repeat this process with the other 5 patties. Place hamburger boats on a cookie sheet that has been lined with foil and bake at 350 degrees for 1 hour. Take hamburger boats out of the oven and carefully unfold the tops( they will be HOT!) drizzle each boat with a little more BBQ sauce and sprinkle with a french fried onions and a generous amount of cheese. Put them back in the oven for 5-10 minutes or until cheese is melted. When they are finished keep them on the cookie sheet, carefully open the foil packs and use a spatula to transfer them to a plate. When handling the foil packs be very careful as there will be hot grease in the bottom of them!