A few hours before you want to grill, begin to marinate your steak. Season well with salt and pepper. Drizzle with olive oil and rub with garlic cloves. Lay fresh herbs underneath and on top of the steak. Cover with plastic wrap and chill in the fridge for a few hours.

Take the steak out of the fridge 30 minutes before you are ready to grill. Heat to high heat, and cook for 4 to 6 minutes on each side. 

Cover the cooked steak with aluminum foil and let rest for 10 minutes. 

While the steak is resting, start the butter sauce. Add a 1/2 cup of butter, 4 cloves of minced garlic, and a generous pinch of salt to a saucepan. Melt over medium-low heat. The garlic will slowly cook in the butter. Slice the flank steak against the grain as thinly as possible. 

Pour garlic butter over steak and sprinkle with chopped parsley.