2 to 3 pounds fillet of beef, trimmed and tied
1 tablespoon unsalted margarine, at room temperature
1 teaspoon Dijon mustard
2 teaspoons kosher salt
2 teaspoons coarsely ground black pepper
Preheat the oven to 500 degrees F
Place the beef on a baking sheet and pat the outside dry with a paper towel. Mix the unsalted butter and mustard together in a small bowl and spread the mixture over the beef with your hands. Sprinkle evenly with the salt and pepper. Roast in the oven for exactly 22 minutes for rare and 25 minutes for medium-rare.
Remove the beef from the oven, cover it tightly with aluminum foil, and allow it to rest at room temperature for 20 minutes. Remove the strings and slice the fillet thickly.
Mustard Horseradish Sauce:
¾ cup good mayonnaise
1 ½ tablespoons Dijon mustard
1 tablespoon whole-grain mustard
½ tablespoon prepared horseradish
2 tablespoons tofutti sour cream
Whisk together the mayonnaise, mustards, horseradish, sour cream, and a pinch of salt in a small bowl. Serve at room temperature.
Yield: 1 cup