Step 1

Combine buttermilk, garlic and rosemary. Grind in a generous amount of pepper. Pour into a zippered plastic bag.

Step 2

Add the steak to the bag, seal and turn it over a few times to make sure the steak is coated. Place in fridge for at least 8 hours, or overnight.

Step 3

Heat grill to high. Grill steak for 4-5 minutes per side for medium rare.

Step 4

Transfer steak to cutting board, cover with foil and let rest for 5 minutes before slicing and serving.