• 4 tablespoons unsalted butter , softened to room temperature
• 2 tablespoons salt
• 1 tablespoon freshly ground pepper
• 4 1/2 to 5 pounds fillet of beef tenderloin , trimmed and tied
• 3/4 cup mayonnaise
• 1/4 cup sour cream
• 1 tablespoon coarse mustard , such as Pommery
• 1 tablespoon Dijon mustard
• 1/4 teaspoon salt
• 1/4 teaspoon freshly ground pepper

Heat charcoal or gas grill. Test temperature with an oven thermometer. With lid on grill, thermometer should register 425° to 450°.

Combine butter, salt and pepper. Using paper towels, pat tenderloin completely dry. Spread seasoned butter over fillet. Place meat on hot grill and close lid tightly. (Grill temperature should remain fairly steady, going no lower than 375°.) For rare to medium-rare, cook tenderloin approximately 30 minutes, turning once during grilling. (Internal temperature of thickest part of meat should read 125°.)

Meanwhile, to make sauce: Whisk together all mustard sauce ingredients.

When fillet is done, place on a cutting board and cover with aluminum foil; allow to rest about 20 minutes. Slice beef and serve with mustard sauce.

Recommended ingredients: Pommery mustard is available at specialty shops or online at www.frenchfeast.com.