Sprinkle 1 ? to 2 pounds of top round beef roast with meat tenderizer or salt. Use your hands to pat the seasoning into the meat. Place the meat in a slow cooker for about 6 to 8 hours, depending of the size of your roast. If the roast beef appears to be done, you may turn off the slow cooker and let the roast sit in its juices, until you are ready to prepare your sandwiches. About ? hour before your prepare your sandwiches, start making your whipped potatoes. When ready to make sandwiches, remove the cooked top round roast from the slow cooker and place it on a platter. Slice it into thin (about ?-inch to 3/8-inch) slices. Use the juices left in the slow cooker to make rich roast beef gravy. When you have your gravy made, your potatoes whipped, and your roast beef sliced, toast 2 slices of whole grain bread for each sandwich. On a serving plate, place one slice of toast. Put a few thin slices of roast beef on top of the toast. Cover with the second piece of toast, forming a sandwich. Use a bread knife to slice the sandwich down the middle into two halves. Spread the halves apart, and place a generous serving of whipped potatoes between the two halves. Now, drizzle a generous amount of gravy over the two sandwich halves and the whipped potatoes. Serve immediately. I served my Slow Cooker Hot Roast Beef Sandwich with Orange-Glazed Beets in a side dish?a beautiful and delicious meal