I make versions of this dish quite often, but the method is pretty much the same. My main variation is on the kind of steak I use. I like using ribeye, but other cuts work just as well. For this version, I used a bavette cut of steak, I fried this in a frying pan and when I was happy with how it was cooked, I removed the steak from the pan and let it rest.
Whilst the steak is resting, in the same pan, I cook the onions and peppers. I usually add some fajita seasoning at this point. For one piece of steak I use one pepper and one onion. Though as I like different coloured peppers, I might use a third of three different kinds.
I do find when I am usually cooking a bavette cut that I undercook it, so after the steak had rested I sliced it and then finished off the steak in the pans with the onions and pepper.
The fajitas I serve with warm tortilla wraps, sour cream, guacamole and salsa. I also like to add some pea shoots into the mix as well and thinly sliced radishes.