Côte de boeuf is an epic thick steak taken from the upper part of a cow's fore rib. It's like a triple-thickness ribeye steak with the rib bone still attached, and it's super flavoursome, in part due to the not inconsiderable amount of fat running through it. It's one of the most expensive steaks you can get, but it's absolutely worth it as a treat every once in a while. I highly recommend it! A côte de boeuf, even a smallish one, will normally serve two people, but if you're alone and very hungry and in the mood for a special and rather decadent meal for one, I could hardly think of a better way to spend the evening.
A serious undertaking
Cooking a côte de boeuf is a somewhat serious undertaking; it's big and expensive so you definitely don't want to mess it up! In my restaurant days I would cook it sous vide in a vacuum bag in a temperature controlled water bath until its inside temperature was around 55C, then remove it from the bag and sear it in a hot pan to get a good caramelised brown crust on it before finishing it in foaming butter with thyme, bay and crushed clove of garlic. For a thick hunk of meat such as this, it's a good strategy because the inside stays uniformly pink whilst the outside is nicely browned. In a typical home kitchen however, this approach usually isn't an option.
However, I have an alternative method which is easier, much faster and gives pretty much just as good results. And my method still includes the best parts of the process, ie: the caramelised brown crust and the foaming butter and herbs! Instead of the sous vide technique, I use a modest oven set to 80C. Simply place the côte de boeuf in the oven (directly on the rack to ensure good airflow) for 30 minutes, turning half way. The idea is to gently increase the temperature of the meat so it's not far off the final cooked temperature. The rest of the cooking process is quicker and easier after this head start. You'll also get a better caramelised crust when searing in the hot pan because the surface of the meat is quite dry from being in the oven.
Season, sear and baste with butter
A word on seasoning: it's a big piece of meat so it should be covered generously in good quality sea salt and cracked black pepper. Don't be shy! Do this just before searing in the hot pan, doing it before the warming phase would cause it to leach out liquid which would make the surface of the meat wet and thus make it difficult to get a good crust.
Sear it in a hot pan until it's nicely browned all over, then place it in a hot oven for a few minutes (turn the oven up to 180C after the 30 minutes of warming). Measure the temperature with a meat thermometer or, if you prefer, a thin metal skewer inserted into the centre of the steak, then touched to your bottom lip. For rare / medium rare, it should be 50C - 55C.
Once it's cooked, finish it in a pan on the stovetop with a large spoonful of butter, some thyme and bay and a large unpeeled clove of garlic lightly crushed with the heel of your palm. Spoon the foaming butter over the steak until it's nutty and brown. Finally, leave to rest on a rack for 10 minutes. Serve it with whatever side dishes you want, but a glass of red wine is obligatory.