Heat outdoor grill or grill pan if cooking indoors (I used a large cast iron grill pan) - it should be smokin' hot (literally!)
Brush grill with additional avocado oil, pastured ghee, or pastured lard. Add the veggies (they should sizzle as soon as they hit the pan) and allow to cook, turning often, until softened and until the edges are nicely charred.
Once cooked, transfer to a warming oven while you grill the meat. (Alternatively, cook the veggies in a large cast iron skillet over the stove while you grill the meat.)
For the meat, brush a fresh layer of oil/ghee/lard over the grill and add the meat (again, you want sizzling). Cook for a few minutes on each side, or until the meat tests around 130 degrees internally (medium-rare to medium). Remove from grill and allow to rest a few minutes before slicing.
After beef has rested, slice it against the grain and serve it and the peppers and onions with tortillas and all the fixin's.