However, itâs also a time to be aware of the dangers soaring temperatures can bring. Extreme heat is the number one weather-related killer in the U.S, claiming more than 650 lives across the nation each year, according to the Centers for Disease Control and Prevention.
1 In a bowl whisk together garlic, extra virgin olive oil, balsamic, 1/4 cup red wine, 1 tablespoon chopped rosemary, salt and pepper.  Place flat iron steak in a resealable plastic bag. Pour marinade over the top. Shake to coat steak in marinade. Refrigerate for 8 hours or overnight.
Best Answer: Flat iron steaks really are not meant to be cooked in the oven. Like flank steak, they benefit from marinating for a long time (at least 6-8 hours-I usually marinate overnight). Then grill or broil. If you go past medium, they tend to become tough.