½cup(1 stick) unsalted butter, at room temperature
½teaspoonfreshly ground pepper
For the Beef Tenderloin
1beef tenderloin(3 to 3 ½ pounds), tied
2tablespoonunsalted butter, at room temperature
1teaspooncoarsely ground black pepper
Make the compound butter: Place the capers, shallot, chives, tarragon, ½ cup butter and pepper in the bowl of a small food processor and process until well blended.
Scrape the butter out on the center of a piece of plastic wrap, and use the plastic wrap to form the butter into a 4-inch long log about 2 inches in diameter. Wrap it well, and refrigerate for at least 2 hours and up to 5 days.
To cook the filet, preheat the oven to 475°F. Pat the filet dry with paper towels, and place the filet on a rimmed baking sheet. Rub the two tablespoons butter all over the meat, and evenly sprinkle the salt and pepper over the surface.
Place the filet in the oven at roast for about 23 to 25 minutes for rare (an internal temp of 120°F, and 27 to 30 minutes for medium rare (an internal temp of 125°F), depending on the thickness of the meat. Let the meat sit in a cutting board, tented with foil for 20 minutes before slicing into thick slices (or thin, your call!). Remove the compound butter from the fridge while the meat rests.
Place a slice of the compound butter on top of the warm slices of meat as you serve them.