Roast Beef Sandwiches with Horseradish Sauce

Prepare rolls according to package directions. Let cool slightly. Cut each roll in half.

Combine sour cream and horseradish in a small bowl; set aside.

Place rolls on a baking sheet cut-side-up. Lightly spray each cut side with nonstick cooking spray. Broil on middle oven rack until lightly toasted, about 1 minute.

Remove top halves of rolls from baking sheet; set aside.  Top the bottom halves of rolls with roast beef and a slice of Swiss cheese. Broil for 4 to 5 minutes or until cheese is melted.

To serve, top with horseradish sauce, lettuce leaves, tomato slices, rings of red onion and tops of rolls.  