In a large mixing bowl, add soy sauce, olive oil, Worcestershire sauce and brown sugar. Whisk everything together until the sugar dissolves. This mixture forms the flavorful base for the marinade.

Add minced garlic, Dijon mustard, black pepper, paprika, onion powder, lemon juice and chopped rosemary. Mix well so the herbs and spices spread evenly through the marinade.

Place the tri-tip roast on a cutting board. Pat it dry with paper towels. This step helps the marinade stick better and improves the final flavor.

Place the beef in a large zip-top bag or container. Pour the marinade over the meat. Seal the bag and turn it several times so the beef is fully coated.

Place the bag in the refrigerator for at least 4 hours. For best flavor, marinate overnight. Turn the bag once or twice to keep the meat evenly coated.

Preheat your grill to medium-high heat or oven to 400°F (200°C). Proper heat helps create a nice crust on the outside of the beef.

Remove the beef from the marinade and let excess drip off. Place it on the grill or baking tray. Cook about 15–18 minutes per side.

Once cooked, remove the tri tip from heat. Let it rest for about 10 minutes. This helps the juices settle inside the meat.

Place the tri tip on a cutting board. Slice thinly against the grain. This makes the meat tender and easy to eat.