Preheat the smoker to 120C/250F using the desired hardwood. I used applewood chips.
Brush the beef with olive oil. Mix together the sea salt, black pepper, dried parsley, and garlic powder and rub over the beef.
Place the beef directly on the smoker and away from the direct heat. Smoke the beef for 1 hour or until the inner temperature reaches 110F.
Transfer the beef onto the grill or a hot cast iron skillet and sear on all sides for 5 minutes.
Allow the beef to rest 10-15 minutes before slicing and serving.
Notes
TO STORE. Allow leftover beef tenderloin to cool completely, then wrap it tightly in plastic wrap or aluminum foil and store it in the refrigerator for 3 to 4 days.TO FREEZE. Place the tightly wrapped beef in a freezer-proof bag or container and freeze for 3 to 4 months. Thaw in the refrigerator overnight before reheating.TO REHEAT. Wrap the meat in foil and reheat it in the oven at 250°F. You can also slice the cold beef and gently warm the slices in a skillet over low heat with a splash of broth or water.