mix vinegar and olive oil together with 1 sprig of rosemary
put marinade in a plastic bag
add steaks and massage outside of bag so marinade rubs onto steaks
place bag on countertop and turn bag over every 5 minutes so both sides of steak marinate. Marinate for a total of 20 minutes.
tie remaining 4 sprigs of rosemary with twine to make a brush
remove steaks from bag and sprinkle with salt and pepper
heat cast iron grill on medium high until hot
grill steaks for 7 minutes and baste with rosemary brush dipped in olive oil
turn steaks over and continue to baste
top each steak with ½ tbsp of butter after 5 minutes
continue to grill for another 2 minutes until butter is melted and temperature is 135
remove from pan and tent with foil.
Let steaks rest for 10 minutes then slice and serve with sprigs of rosemary and roasted whole garlic