Cast iron grate. We've cooked steak exclusively on the mini for the past year, and I wasn't completely happy. I was going to do a reverse sear for the first time, and then I got a CI grate. No fuss. Heated it up to 475, cooked the 1-inch boneless rib eye for three minutes on each side, and perfection. Fantastic sear and medium rare throughout. (No pics. Just can't get the husband to buy into pics instead of eating.) CI has earned a place on my essentials list.
Owner of a large and a beloved mini in Philadelphia