Oven-Cooked Top Sirloin Steak

Bring the sirloin steak to room temperature for at least 30 minutes before cooking. Immediately pat dry the steak on both sides, then season generously with sea salt. When you're ready to sear, pat the steak dry a final time.
Preheat your oven to 400°F.
Heat an oven-safe skillet on high heat and when it's ripping hot, add the olive oil. Add the steak to the hot skillet and sear for 1 to 2 minutes on each side, or until a golden crust has formed. For thinner steaks, lean on the side of caution. If you have a metal burger press, use it to press down the steak to develop a better crust.
Top the steak with butter and rosemary, then insert a meat thermometer into the steak for more accurate temperature readings. Transfer to the oven to finish cooking, and flip the steak halfway through.
Once your steak reaches your desired temperature (see above table for details), take it out the oven and set it on a cutting board (preferably wooden). Let the steak rest for 10 minutes, garnish with black pepper and more salt, then cut into slices.