Slice a cross hatch pattern on the fat cap (if there is one) without cutting into the meat. If the fat cap has been trimmed you can skip this step.
Rub dry-rub spices on both sides of the meat and let meat sit at room temperature for 30 minutes.
Heat an oven-proof pan over medium heat with a little avocado or olive oil and place a seasoned tri-tip fat cap side down and sear for 7 minutes or more over medium heat until a good crust has formed.
After 7 minutes, take a peak and see if there is a nicely browned crust, if not let it go for another couple minutes. Once there is a good crust, flip and place in an oven preheated to 425 degrees.
Once you flip the tri-tip, place in a 425 degree oven and cook to your desired temperature—a good start is 10 min per pound for medium rare (125 degrees).
Let tri-tip rest for at least 10 minutes and up to 20 minutes under foil.