Trim excess fat and silver skin from the flank steak
Pat the steak dry
Season both sides with salt, pepper, and any desired spices or marinade
Let the steak rest at room temperature for 20 to 30 minutes
Preheat a grill, skillet, or broiler to high heat
Cook the steak for 3 to 5 minutes per side for medium-rare, depending on thickness
Use a meat thermometer if desired; remove at 130 to 135°F for medium-rare
Avoid overcooking to keep the meat tender
Transfer the steak to a cutting board and rest for 5 to 10 minutes
Slice thinly against the grain
Serve immediately