Roast Beef Sandwich on Sourdough Bread This particular roast beef sandwich recipe uses round sourdough bread, but is just as delicious on any of your favourite breads. For convenience, you can buy pre-sliced roast beef at your local deli for these sandwiches. 1 6oz jar of horseradish 1/2 cup reduced-fat/non-fat sour cream 1 jar of dill pickles 1/4 cup reduced-fat/non-fat mayonnaise 2 teaspoons whole-grain Dijon mustard pinch of salt 1/4 tsp freshly ground black pepper 2 cups chopped red cabbage 2 crusty sourdough breads, 6-8 inches diameter 1 Granny Smith apple, cut in half and cored 2 teaspoons fresh lemon juice 3/4 pound thinly sliced Gruyère cheese 1 pound thinly sliced rare roast beef Combine together the horseradish, sour cream, pickles (chopped), mayonnaise, mustard, salt and pepper in a large bowl, until well blended. Add the cabbage and stir to combine. Set this mixture aside. In a separate bowl, slice the apple halves very thinly and coat with lemon juice. Slice the sourdoug