Pat the flank steak dry
Season generously with salt and pepper
Add any desired dry rub or marinade
Let the steak sit at room temperature for 20 to 30 minutes
Preheat a grill, skillet, or broiler to high heat
Lightly oil the cooking surface or steak
Cook the steak for 3 to 5 minutes per side for medium-rare, depending on thickness
Check for an internal temperature of 130 to 135°F for medium-rare
Remove the steak from the heat
Let it rest for 5 to 10 minutes
Slice thinly against the grain
Serve immediately