In a small mixing bowl whisk together the salt, garlic powder, onion powder, oregano, rosemary, cayenne pepper, paprika, black pepper, and dried sage.
Rub the seasoning all over the beef; set aside and let it rest for 30 minutes to 1 hour. You can also cover and refrigerate it for up to 24 hours before cooking. Make sure to take it out of the fridge at least 30 minutes before you intend to cook the meat.
Preheat the oven to 400˚F.
Heat vegetable oil in a large cast iron skillet (or any other oven-safe skillet) set over medium-high heat.
Add the sirloin tip to the heated skillet, smooth side down; cook for about 3 minutes on both sides or until nicely browned.
Remove the skillet from the burner and transfer it to the oven; roast for 25 to 35 minutes or until the roast's internal temperature registers at 125˚F to 130˚F. Cooking time will depend on the weight and size of the sirloin tip.
Remove from the oven and transfer the roast to a cutting board; cover loosely with aluminum foil and let it rest for 10 to 15 minutes.
Slice the roast thin against the grain, garnish with parsley, and serve.
Notes
Marinate: Season the roast and let it chill in the fridge for up to a day for enhanced flavor.
Seasoning: Note that if the roast you are using is under 3 pounds, you may want to use less seasoning.
Rest the Beef: Allow the sirloin to rest post-seasoning for up to an hour and another 15 minutes post-roast for maximum juiciness.
Skillet Choices: Cast iron is excellent, but any oven-friendly skillet will do the job seamlessly.
Check Doneness: Use an instant-read thermometer and pull the roast at 125ºF to 130˚F. It will continue to cook while it rests.
Slice Right: Cut against the grain for the most tender result.