Begin by taking your porterhouse steak out of the refrigerator about 30 minutes before cooking to allow it to come to room temperature. Pat the steak dry with paper towels.
In a small bowl, mix together the onion powder, garlic powder, sea salt, and pepper. Rub this seasoning mix all over the steak, then drizzle with olive oil.
Take the fresh herbs—rosemary, sage, and thyme—and tie them together with butcher's twine.
Place a cast iron skillet over high heat or preheat your grill. Add a little olive oil to the pan if using a skillet.
Once the skillet is hot, place the steak in the pan and do not move it for about 4-5 minutes.
After 5 minutes, flip the steak and add the herb bundle and melted unsalted butter to the pan.
Baste the steak with the melted butter and herb mixture. Continue cooking for another 4-5 minutes for medium-rare.
Once cooked, allow the steak to rest before slicing.
