Ingredients

• 1/4 cup nonfat Greek style yogurt or 1/3 cup regular, plain nonfat yogurt
• 2 tablespoons mayonnaise
• 1/4 cup prepared white horseradish, squeezed of excess juice (about 3 tablespoons)
• 1/4 teaspoon salt
• 1/8 teaspoon pepper
• 1 bunch watercress, thick stems removed
• 8 slices whole-grain pumpernickel bread
• 12 ounces lean roast beef, thinly sliced
• 2 medium tomatoes sliced
• 1/2 small red onion, thinly sliced

Instructions

1. If using regular yogurt, place it in a strainer lined with paper towel and set the strainer over a bowl. Let the yogurt drain and thicken for 20 minutes.
2. Combine thickened or Greek-style yogurt, mayonnaise, horseradish and salt and pepper in a small bowl and stir to incorporate.
3. Place 1/4 cup watercress each on 4 slices of bread and drizzle with 2 tablespoons horseradish mayonnaise. Layer with 3 ounces roast beef per sandwich, tomato slices and onion slices. Top with another slice of bread and wrap in waxed paper, then aluminum foil.