Put the sliced onions in a bowl of cold water to take the bite out if them while you prepare everything else.

Combine the Worcestershire and hot sauce in a bowl large enough to hold the steak. Prick the steak all over with a fork and then add it to the bowl with the sauce. Let that rest in there while you make the butter.

Mix together the butter, blue cheese, and 1/2 tablespoon of the parsley with some salt and pepper. Reserve for later.

Heat a large cast iron skillet over high heat and add 1 tablespoon of oil then add the steak. Do not move it until the bottom browns, about 5 minutes. Flip and cook for at least another 5 minutes, use a thermometer in the thickest part of the meat to be sure. You may need to lower the heat a bit, You want 140 to 145 for medium rare. When it is just shy of the desired temp remove from the heat, cover with foil, and prepare the salad.

Drain the onion and combine it with the sliced celery, 1/2 tablespoon of oil, remaining parsley, juice from half the lemon salt and pepper.

Slice the steak and divide it among the plates, top with blue cheese butter and serve the salad along side.