Preheat oven to 475 degrees.

Rinse meat well. Trim away a little of the fat. You'll want to leave a little fat on for flavor.

In a small bowl, mix together the salt, garlic powder, onion powder and black pepper.

Sprinkle the meat generously with the salt and spice mixture. Rub it in with your fingers and make sure the entire piece of meat is completely covered with the salt and spice mixture.

Place the peppercorns in a Ziploc bag, and with a large hammer or mallet, begin to smash the peppercorns to break them up. Set aside.

Heat the olive oil in a heavy skillet. Place the tenderloin in the pan to sear one side. Add a tablespoon of the butter to the pan. After a minute or two, turn the meat over and sear the other side.

Place the tenderloin on an oven pan with a rack. Sprinkle the peppercorns over the meat and press onto the meat.

Break up and place the remaining butter all over the meat.

Stick the needle of meat thermometer into the meat.

Place in the oven until the temperature reaches 140 degrees, about 15 to 20 minutes. Be sure keep a close eye on the meat cooking to make sure it doesn't overcook.

Remove the meat from the oven and cover the pan with a sheet of aluminum foil. Let the meat stand for 10 to 15 minutes before slicing.