In a small bowl add all spices and blend together. Place sirloin cuts on a cutting board and season with dry rub on both sides. If you have time, I recommend letting the meat sit and marinade at room temperature before cooking. I often suggest 30 minutes.

Put the meat to the side and begin chopping up all of your taco ingredients: onions, bell peppers, tomatos, avocado and anything else you want to add. Cook your taco shells after your taco condimients are ready and set aside in a 250 degree oven to keep warm.

Be sure before putting the meat on the grille that you get your cast iron grille good and hot. Place meat on grille and cook for 3-4 minutes turning diagonally and cooking for another 3-4 minutes before turning over and cooking on the other side. This will give you great criss-cross grille marks.

Remove meat immediately and let rest for a few minutes before slicing in 1/4 inch slices across the grain.