ROAST BEEF SANDWICH w/ WATERCRESS & HORSERADISH

From Ellie Krieger's SO EASY


For the sauce:


1/4 cup plain Greek-style nonfat yogurt
1/4 cup prepared white horseradish, squeezed of excess juice (about 3 tablespoons)
2 tablespoons mayo
1/4 teaspoon salt
1/8 teaspoon freshly ground black pepper

For the sandwich:


1 bunch watercress, thick stems removed
8 slices pumpernickel bread
3/4 pound lean roast beef, thinly sliced
2 medium tomatoes, sliced
1/2 small red onion, thinly sliced

To make the sauce, combine the yogurt, horseradish, mayo, salt and pepper in a small bowl and stir to incorporate.  The sauce will keep for up to 5 days in an airtight container in the refrigerator.

To make each sandwich, place 1/4 cup of watercress on a slice of bread and drizzle with 2 tablespoons of the sauce.  Layer with a few slices of roast beef, then some of the tomato and onion slices.  Top with another slice of bread and serve or wrap in foil to go.  YIELD:  4 servings