Pat the flank steak dry
Season both sides with salt and pepper
Optional: add garlic, oil, or marinade
Preheat a grill, skillet, or broiler to high heat
Cook the steak for 4 to 6 minutes per side for medium-rare, depending on thickness
Use a meat thermometer if desired
Remove the steak when it reaches your preferred doneness
Let the steak rest for 5 to 10 minutes
Slice thinly against the grain
Serve immediately