Remove the steaks from the fridge about 30 minutes before cooking. Season them well with salt. Use a cast iron skillet if you have one. The next choice would be stainless steel and always avoid non-stick skillets.
Sear the steaks and cook to your desired doneness. For a rare steak, cook it 7 minutes, 3 ½ on each side. The internal temperature will be 115-120 Fahrenheit.For a medium rare steak, cook it 8 minutes, 4 on each side. The internal temperature will be 130-140 Fahrenheit.For a medium steak, cook it 9 minutes, 4 ½ on each side. The internal temperature will be 140-150 Fahrenheit.For a medium well steak, cook it 10 minutes, 5 minutes on each side. The internal temperature will be 150-156 Fahrenheit.And for a tragically well done steak, cook it 12 minutes, 6 minutes on each side. The internal temperature will be 160-210 Fahrenheit.
Remove the steaks to a platter, then add butter, fresh rosemary, and garlic to the skillet. When the butter is melted, return the steaks to the skillet and spoon the butter over them.
Remove the steaks to a platter and deglaze the skillet with cognac. You can light it on fire, if you want! Add creme fraiche and lots of freshly ground pepper!
Notes
For the two of us, I buy a Porterhouse steak because he likes the strip and I like the filet. We both win.If you can't find creme fraiche, you can substitute sour cream.If you can't handle that much black pepper, reduce it to your liking, but to be Steak au Poivre, it should have a fair amount!