Place whole peppercorns into a ziplock bag, then crush with a kitchen mallet or rolling pin. Set aside.
Place trimmed beef tenderloin onto a cutting board or clean large surface and season liberally with the seasoning salt and the salt. Watch the video to get a better idea.
Turn the ends of the tenderloin into itself so the thinner ends are now in the middle of the tenderloin.
Place 3-4 pieces of cooking twine under the tenderloin and tie into knots, trimming the ends, so that the ends stay put and the meat is not wrapped into a nice rectangular shape that will fit into a skillet.
Heat butter and olive oil over medium-high heat in an oven-safe skillet.
Using tongs, place the whole tenderloin into the pan. Sear for 3 minutes, then turn. Repeat until all 4 sides are seared.
Place seared tenderloin onto your oven's roaster pan. Spread the crushed peppercorns onto the steak, place butter cut into chunks over the steak, and place an oven-safe meat thermometer into the tenderloin.
Cook for 15-20 minutes or until the thermometer reaches 140 degrees.
Let thetenderloin rest for 10 minutes before slicing
Make sure to slice against the grain for tender slices of tenderloin.