When a dish is this simple it’s important to use the best meat, the best salt and the very best balsamic vinegar you can find.
The butter may not be necessary on very high quality cuts of “prime” beef. However “prime” is not typically available in consumer markets.
Also, this recipe is for an extra-thick 2‑inch t‑bone steak. Ask your butcher to special cut this for you, otherwise the cooking method and time will need to change appropriately.
- 1 T‑bone or Porterhouse steak (2‑inches thick) about 1 ½ lbs
- ¼ cup olive oil (plus more for brushing on steak)
- 2 red onions (peeled and quartered with root end attached)
- 3 clove garlic (peeled and minced)
- 1 tablespoon minced thyme leaves
- coarse sea salt (such as Maldon)
- freshly cracked black pepper (as needed)
- ½ cup balsamic vinegar
- 1 tablespoon unsalted butter (cut into chuncks) optional
Bring the steak to room temperature at least 30 minutes before cooking.
Once the steak comes to room temperature, place the oven racks in the top and center positions; preheat the oven to 450 degrees F.
Heat ¼‑cup olive oil in a large, ovenproof sauté pan set over medium-high heat. Once the oil begins to shimmer, add onion quarters and lower the heat to medium; cook, carefully turning occasionally until lightly browned on all sides. Add the minced garlic, thyme and a pinch each salt and pepper; cook until fragrant, about 1 minute. Carefully de-glaze the pan with the vinegar, then spoon a bit of the liquid over each of the onion quarters. Move the pan to the center rack of the heated oven; roast until tender and well-browned, about 20 minutes depending on the size and water content of the onions. Watch them carefully. They may be made up to 8 hours ahead. Reheat before serving.
Meanwhile, coat with more olive oil and liberally season the steak with the salt and pepper. Press the seasonings into the meat to be assured that they adhere. Place a large cast iron or other non-stick ovenproof skillet over medium-high heat. Let the pan get very, very hot. Carefully lay the steak into the pan. Turn the exhausts fan to high and prepare to work quickly.
Cook the steak on one side for 2 or 3 minutes, then quickly flip the steak and place it on the top shelf of the heated oven (this is a good time to check the onions if you are cooking them together). Roast the meat 4 to 5 minutes for a rare steak, a couple of minutes more for medium-rare. Use in insta-read thermometer to assure the meat is cooked to your liking. Rare no more than 125 / Medium rare 130–135 / Medium 135–140.
Just before removing the steak from the oven dot it with a few chunks of butter (if using). Leave the buttered steak in the oven another minute of so to “cook” the butter as opposed to merely melting it. Remove the cooked steak from the pan and place it on a cutting board to rest 5 to 7 minutes.
If the onions came out of the oven before the steak, stick them back in to quickly reheat them while the steak rests. To serve, cut the meat off the bone, then carve into slices. Arrange the meat onto individual plates and top with the onions. Drizzle pan juice and and any accumulated liquid left on the cutting board over each plate. Serve immediately.
For pan roasting, heat a cast iron skillet with a little olive oil until smoking hot. Turn on the fan, open the window and stand back to avoid getting splattered! Using tongs, place the steaks in the center of the pan. Cook until the first side is seared brown, about 4 minutes. Turn the steaks and place the pan in the oven until the steaks are done, about 6 minutes for medium rare. Remove the steaks to a carving board and let rest for at least 5 minutes before carving.
Cut the steaks away from the bone and carve into ½‑inch slices. Arrange the meat on warmed plates and drizzle a little bit of balsamic vinegar over the slices. Serve with some extra gray sea salt on the side.