Place eye of round in the slow cooker. Add spices and 2 cups of water. Cover, and cook on high heat for 7 hours (you don't want it falling apart). Remove meat from crockpot, and slice thin (approximately 1/2") with an electric knife. At this point, the inside of the meat will be a little dry. Return meat to crockpot, on low, for 1 more hour. This helps give it added moisture and flavor!
After one hour of simmering in the juices, place two slices of meat on each toasted roll, top with provolone cheese. Return to toaster long enough to melt cheese. Serve with horseradish sauce.
Divide leftovers into individual or family sized portions, and freeze for an easy dinner! Reserve/freeze broth for another occasion.