准备

干年龄牛肉提前三到七天：

• 拆开牛肉，用纸巾干洗，然后用纸巾拍干。不要修剪。将烤肉松散地包裹在三层奶酪块中，然后将其放在有框的烤盘或其他托盘上的架子上。冷藏三到七天；牛肉年龄的时间越长，获得的越来越美味。第一天之后，小心地解开包装，然后用相同的奶酪夹子重新包装，以防止布纤维粘在肉上。
• When ready to roast, unwrap the meat and, with a sharp knife, shave off and discard the hard, dried, outer layer of the meat. Shave away any dried areas of fat, too, but leave behind as much of the good fat as possible.

Roast the beef:

• Mince the garlic cloves with a chef’s knife and sprinkle with the salt. Using the side of the knife, scrape and mash the garlic and salt together until they turn into a paste. In a small bowl, combine the garlic paste with the mustard, thyme, olive oil, and pepper. Rub the garlic mixture over all sides of the beef. Put the roast, fat side up, on a rack set in a heavy-duty rimmed baking sheet or small roasting pan. Let the roast sit at room temperature for 1 hour. Meanwhile, position a rack in the center of the oven and heat the oven to 450°F.
• Roast the beef for 15 minutes. Without opening the door, reduce the oven temperature to 375°F. Continue to roast until a thermometer inserted in the center of the roast registers 130°F for medium rare, 1 to 1-1/2 hours.
• 让牛肉休息20分钟。同时，将CrèmeFraîche转移到一道小菜中。将牛肉雕刻成薄或厚的切片，然后穿过侧面的奶油。