Thaw the beef roast, if frozen. Use meat tenderizer to salt and tenderize the beef to taste. Grind some peppercorns (or use regular black pepper) over the top of the meat, to taste. Place the beef roast in a crock pot and cook on low all day for a dinner meal (roughly 6 to 8 hours). When ready to serve, remove the cooked roast beef to a tray or cutting board. Slice into desired serving pieces and place on a serving platter. Now, make your roast beef gravy. From the juices that are left in the crock pot, spoon off as much fat and beef slivers as you can, and then pour the juices into a saucepan. Mix together 1/4 cup cornstarch and 1 cup water, and add to the saucepan of juices. Stir thoroughly before putting the saucepan over heat. Now, move the saucepan to a burner on your cooktop. Turn the heat on to low, and cook the gravy, stirring constantly. If the gravy is too thick, add a little water at a time until it is smooth and of perfect consistency. In making this recipe, I added 1 extra cup of water to thin the gravy to a perfect consistency. Serve while hot!