In a mixing bowl, combine horseradish ingredients together and season to taste with pepper.
Trim mustard greens of any tough stems. Wash and dry. Roll leaves into a tight, long cylinder and cut across roll in 1/4-inch slices. Melt butter in a saute pan over high heat. Saute greens with salt and pepper just until wilted, about 2 to 3 minutes. Remove from pan and reserve.
Lower heat and add bacon to pan. Cook bacon until heated through, about 1 minute per side.
Assemble sandwiches: Toast 12 pieces of potato bread and spread 6 with Horseradish and Mustard and Mayonnaise. Cover the 6 coated pieces of toast with mustard greens, bacon, and thinly sliced tomatoes. Melt butter in a large skillet over moderate heat. Fry eggs until yolks are just set, about 1 minute per side. Set each egg atop a plain piece of toast. Place egg covered piece on top of tomato to form a sandwich. Slice in half and serve with cole slaw, olives and French fries.
c.1997, M.S. Milliken & S. Feniger, all rights reserved