Holiday Tenderloin with Caviar

- 1-1/2 pounds beef tenderloin, trimmed
- 2 teaspoons Dijon mustard
- salt and freshly ground pepper
- 1/2 cup dairy sour cream
- 2 tablespoons well-drained horseradish
- 3 Bays English Muffins, split
- 1 small red onion, thinly sliced
- 1 ounce caviar, such as bowfin, whitefish or salmon, or a combination
- watercress

Rub tenderloin with mustard; sprinkle with salt and pepper. Place in oiled 9-inch square baking pan and roast in preheated 425ºF oven 20 to 25 minutes until meat thermometer registers 135ºF. Remove from oven, cover with foil and let stand 10 minutes. Combine sour cream and horseradish. Toast muffin halves and place one half on each plate. Slice tenderloin and place two slices on each muffin. Top with a slice of red onion, a dollop of horseradish-sour cream mixture, and caviar. Garnish with watercress.

Note: Leftover roast beef or beef tenderloin can also be used.

Serves 6