Use paper towels to pat dry the beef roast.
Sprinkle the roast with flour, gravy master, Kinders seasoning, salt and pepper to taste. Use your hands to spread over the top of the roast.
Heat the olive oil in a Dutch oven over medium to high heat. Sear the roast on all sides, browning it. Use a pair of tongs to turn the roast.
Place the sliced onions in the pot, around the roast in either a Dutch oven or metal roasting pan. Sprinkle the onion soup mix around the roast.
Pour the apple cider around the roast and cook, uncovered in a preheated 350 degree F oven for about 3 to 3 ½ hours, or until the meat is tender. Baste the meat with the juices occasionally.
Place the roast on a cutting board and slice it thinly. Place the sliced meat back into the juices.
Turn the oven up to 375 degrees F. Place your rolls in the oven for 5-6 minutes to make them crunchy. Slice the rolls and place the bottoms on a half sheet pan lined with parchment paper. Place a layer of meat on the bottom, then onions and drizzle with a little au jus.
Top each sandwich with several slices of cheese. Place the sandwiches on a half sheet pan into preheated oven for 4-5, or until the cheese is melted. Place the top of the sub roll on and enjoy. Dip in remaining au jus.