Mix all the ingredients for the marinade and rub all over the steak. Put aside to marinate for 15 minutes, or ideally over night if possible, but not necessary.
Add cooking oil and butter to a cast iron pan or oven proof pan, and heat to medium high. Sear tri tip fat side down for 3 minutes, and then flip over and cook for another 3 minutes.
Pour marinade sauce over tri tip and place in oven.
Roast for 12 minutes per pound. This should cook the beef to a medium to medium rare. Best to use a meat thermometer for your desired temperature.
While your meat is roasting, mix all ingredients together for the dipping sauce.
Let it sit so all the flavors can infuse together.