Add all marinade ingredients to a large bowl and whisk to combine.

Place your tri-tip in a large storage bag and pour marinade over the roast. Seal bag and gently shake bag around to fully coat the roast. Place in the fridge for at least 8 hours but ideally 24 hours. Flip bag over about halfway through to make sure the roast is evenly marinating.

Preheat oven to 400 degrees.

Heat a cast iron skillet to high heat. Once very hot, add oil and begin to sear the roast on all sides for about 2 minutes until there is a nice char.

Transfer skillet to the preheated oven and bake for 20-30 minutes depending on your preferred doneness. 130 degrees for rare, 140 degrees for medium-rare, 145 degrees for medium. You will need a meat thermometer to check the temperature.

Once done, remove from oven and let rest for 5-10 minutes. Slice and serve.