Heat the sous vide water bath to 133 degrees for a medium-rare finish. 145 for well-done pork tenderloin.

Remove the silver skin from the pork tenderloin as this can become tough.

Sprinkle Montreal Seasoning all over the pork tenderloin.

Seal the pork tenderloin in your vacuum sealer (or use a high quality zip top freezer bag) using the moist seal setting.

Place the pork into the water bath and cook for 2 to 4 hours.

Remove the pork from the water bath, open the bag and allow it to rest while heating the skillet.

In an iron skillet or other heavy pan, heat butter and olive oil until butter just starts to brown.

Reverse sear the pork tenderloin by carefully, placing pork tenderloin into hot butter/oil and browning each side. Achieving a brown crust will only take 45-60 seconds per side.

Slice the pork against the grain.

Use the pan drippings as a sauce if you desire.