Prime rib is a cut from the top loin of beef. It is considered one of the most flavorful cuts of beef. The meat is tender and has a rich flavor that is enhanced by cooking it at a low temperature for a long time. Beef prime ribs are usually served with a sauce made out of wine and stock. Some restaurants serve it with mashed potatoes and other side dishes such as broccoli rabe or Brussels sprouts. It’s important to note that while prime rib is cut from the top loin, the rest of the animal makes up the bottom half of the cow. So if you buy a whole cow, the prime rib will be on the top portion of the carcass. This is also known as the “top sirloin” or the “center-cut.”