1. Pat the tri-tip dry and trim lower fat if untrimmed. Leave fattier layer if present. Season the beef cut generously with black pepper and salt.
2. Blend the marinade ingredients in a bowl and rub it over the tri-tip. Keep it in a plastic bag and refrigerate it for one hour. Bring out the beef cut and leave it to sit at room temperature for five minutes. Set the oven to preheat at 425F while you wait.
3. Cook the olive oil in a cast-iron skillet at high heat and sear the tri-tip, fat-side-down. Reduce the heat to medium-high and let it cook for five minutes- by now, it’s browned. Flip the beef cut and cook the other side for another two minutes.
4. Transfer the beef cut with the skillet to the oven and roast at 15 minutes per pound. Inspect the internal temperature with a meat thermometer for preferred doneness.
5. Once it’s done, tent the tri-tip on the counter with foil to rest for five to ten minutes. While it cools, boil the marinade in a saucepan over medium-high heat till it thickens. Adjust the salt and pepper to taste, and serve with the tri-tip. Slice the beef cut halfway against the grain on its ends and at the center point.

If you want more clues, check out this video recipe.