Turn the grill to high heat. To season 1 ½ lbs of top sirloin, use 1 teaspoon of salt, pepper, and mesquite seasoning, all separately. Set the grill to direct heat and cook the steak for three to five minutes per side, or until it reaches a temperature of 145°F.

Marinate the steak: Place the steak in a resealable bag. In a bowl, mix about 1/2 the packet of fajita seasoning, lime juice, and 1/4 cup olive oil. Pour the marinade over the meat and make sure it completely coats the steak. Marinate in the fridge or cooler for at least 2 hours, up to 24 hours.* I prefer to do this step at home.

Use a heat to cook the vegetables in a cast iron pan. Mix them around a lot until they get a little burned and soft, but not mushy. That will depend on your fire, but it should take between 5 and 10 minutes. So the pan doesn't get too full, you might need to do this in two parts.

For about 5 minutes on each side, cook the steak on high heat on the grill until it's medium-rare or medium. Take the steak off the heat and set it down on a cutting board to rest.

Lastly, heat your tortillas on the grill and prepare the cilantro, shredded cheese, and sour cream. Squeeze lime over top.

Slice the steak into thin strips. Assemble the tortillas with steak, veggies, and all the toppings.