Dijon-style mustard, horseradish, and mayonnaise flavor this quick lunch or dinner sandwich.
Combine mayonnaise dressing, mustard, and horseradish in a small bowl. Carefully slice bread in half horizontally using a serrated bread knife. For each sandwich, spread cut side of a bread half with mayonnaise mixture. Top each with roast beef, red pepper strips, cheese, and watercress. Fold bread in half over filling or roll wrap-style. Makes 4 servings.