This particular recipe is for "rock salt roasted prime rib of beef", or something like that. The roast is buried in rock salt, which keeps the outside from getting burnt and absorbs fat/etc while the roast cooks in a rather hot oven. (In general, the difficulty with large roasts like prime rib is getting the inside and the outside cooked to edible doneness levels at the same time.)
- Prime rib of beef. These show up in normal markets around major holidays, and are probably in your better butchers and wholesale clubs and such all the time, or perhaps can be ordered. These days a prime rib roast is available either boneless or with the ribs still attached; cost per pound is somewhat less for the bony version, but cost per roast is about the same (based on my looking at CostCo.) I usually get boneless roasts for convenience of carving and serving; other people believe that the bones add flavor. I don't have any particular hints on how to tell a good roast from a bad roast; you pretty much have to trust your butcher. A whole prime rib will weigh more than 15 pounds and cost over $100. But it will feed 20+ people, so that's not really as bad as it sounds. Hereafter the roast shall be referred to as "the Beast."
- Large Pan. This should be large and deep enough to contain the whole Beast in all three dimensions, plus enough room for the salt.
- Rock salt. Enough to bury the whole Beast. About 10 to 15 pounds. You probably don't want to use rock salt that is targeted toward melting ice on driveways; the stuff I use claims to be for making homemade ice-cream.
- Other seasonings to taste. Or not (see later.)
- Meat thermometer. There are two common varieties of meat thermometer. One is designed to sit in your roast in the oven while it cooks. The other is an "instant read", that you're supposed to stick in to check the temp, but NOT leave in the oven... The former is preferred, so you can keep a continuous eye on how the cooking is proceeding.