Preparing prime rib: A few tips

The only real secret to roasting a great prime rib is starting with the best meat possible, and the rib roast I ordered from McCall’s Meat & Fish Co. in Los Feliz was so beautiful I badgered my husband to photograph it before it went into the oven. I admired its plump, sturdy shape, the way butcher Nathan McCall had neatly frenched the bones and tied up the roast with precisely spaced knots.

It was all natural — no hormones, no antibiotics — Prime Angus beef. At $17.99 a pound, it cost just over $140. Considering that I fed six for the dinner party and had enough left over for dinner for four, that’s about $14 per person — not a crazy extravagance.

McCall also threw in detailed instructions on how to cook it to a true medium rare:

Bring the beef to room temperature, season with salt and pepper and chopped fresh thyme. Put it in a roasting pan and roast in a slow 225-degree oven to an internal temperature of 120 to 125 degrees, for medium rare (emphasis on the rare, as it turned out). That took 2 1/2 to three hours for our 8-pound, four-bone roast. A full rib roast, which can weigh 12 to 16 pounds, will take four to six hours. Baste from time to time with a light brown butter in which 10 garlic cloves have been cooked until soft, and a sprig of thyme. Forty-five minutes before the roast is estimated to be done, mash the garlic into the remaining butter to make a paste and spread it over the outside of the roast, where it will caramelize and give some crunch. Oh, and when you’re timing the roast, remember that the beef should rest for about an hour after it comes out of the oven. That’s it.

I ended up cooking mine to 122 — or so I thought. Each time I probed a different part of the roast, I got a different reading, sometimes by as much as 10 degrees. Next time, I think I’ll cook it 3 to 5 degrees higher, probably to 125, and then as it rests, it should reach 130. As it turned out, my prime rib was a bit too rare for half my guests.

The next day, devil the ribs: Cut the ribs apart, leaving as much meat as possible. Brush with Dijon mustard mixed with minced shallots. Roll in breadcrumbs. Drizzle with a little oil. Bake at 400 degrees until brown and crisp. With a potato gratin: pretty terrific.

irene.virbila@latimes.com