Grilled Spicy Lemon Pesto Flat Iron Steaks are delicious. Flat iron steaks are also known as top blade steaks. Flat iron steaks benefit from marinating. You can substitute flat iron steaks in any recipe calling for flank or skirt steak. This cut is best grilled over a medium-high heat. Don't go as hot as possible unless you pick up a very thin cut. Because of the density of the meat, it is generally best to start with a quick sear before moving to a lower temperature to finish off to the desired doneness.