Preheat the oven to 425 degrees
Heat a heavy iron skillet over high heat for 10 minutes until very hot.
Add olive oil to bottom of pan
season steak with pepper and brown steak on both sides (1-2 minutes to brown)
In a baking dish, press the coarse sea salt (it should be moist, add water if it isn’t) to baking dish and place the rosemary over the salt. Make sure to encase the steak in the salted baking dish.
Bake for 30 minutes for rare and 40 minutes for medium rare.
Make the herb butter during the baking of the steak by combining the ingredients for the herb butter.
Remove steak and let stand for 5 minutes.