Preheat oven to 425 degrees (F).

Rinse tenderloin and pat dry with paper towels. Season with garlic salt and lots of pepper. Lightly sear entire tenderloin in skillet with oil over medium high heat. Remove tenderloin from heat, let slightly cool.

Coat tenderloin with 1/2 cup of pepper butter.

Roast in oven for approximately 50 – 55 minutes or until internal temperature reaches 155 degrees (F). Remove from oven. Allow to rest for at least 10 minutes before slicing.

In a microwave, heat remaining 1/2 cup of pepper butter for about 30 – 40 seconds. Drizzle warmed pepper butter over sliced tenderloin.