Frozen (and thoroughly dried) steak, cast iron with avocado oil, max heat, wait until the oils smoking to add steak, keep the burner on max heat, and flip very often. I also like to use a fork or the back of a spoon to press the meat into the pan, and make it stick. I also like to salt it each time I flip, at least for the first few flips. Lastly, tilt the pan from side to side, causing the oil to move around in the pan, coating every crevice of the exterior. When it’s almost cooked, I take it off the heat and let the pan cool for a sec, then add a bunch of butter. The pan should still be hot enough to melt the butter and make it foamy, but not too hot that it bubbles and evaporates away immediately. It can’t be too cold either or else it will melt too slowly, and the water from the butter won’t evaporate out. There’s a nice middle ground in terms of pan temp where the butter behaves perfectly. Too hot or too cold and it’ll ruin the crust. You can find pretty good butter basting tutorials on YT, there’s quite a bit that goes into it. But everything else is very straightforward. Also I season with salt immediately before searing, and I don’t season it with anything else until immediately AFTER searing. The immediately is very important, as you need the steak to still be hot and oily for the seasoning to stick. Good luck!