In a small mixing bowl, whisk together the olive oil, lemon juice, green onion, chopped rosemary, minced garlic, kosher salt, and red pepper flakes. Rub on all sides of the roast. Marinate in the refrigerator for 24 hours.
Remove the roast from the refrigerator 30 minutes prior to roasting. Preheat the oven to 300°F
Remove from marinade. Brush off as much of the green onion and garlic as possible. Sprinkle liberally with your favorite steak seasoning and a dusting of smoked paprika.
Heat a few drizzles of olive oil on high in an oven safe grill pan or large skillet. Sear the roast for 3 minutes on all 4 sides.
Place the roast into the oven and roast fat side up for 15-20 minutes per pound or until it reaches an internal temperature of 125-130°F for medium rare 140-145°F for medium. Remove from the oven
Rest for 15 minutes uncovered for medium-rare or loosely tented with foil for medium.
Carve thinly and serve.