In the eighteenth century, Irish stew was traditionally made of mutton (usually neck), potatoes, onions, and parsley, although some cooks added turnips or parsnips, carrots, and barley. Mutton was the dominant ingredient because of the economic importance of wool and sheep’s milk in Ireland: only old sheep ended up in the stew pot, where it needed hours of slow boiling before it was palatable. This stew was recognized as an Irish national dish about 1800.
In the United States, Lee’s The Cook’s Own Book includes a recipe for Irish stew that is made from the same ingredients and in the same way as in Ireland. However, in America, Irish stew evolved. As sheep were not plentiful, other meats were substituted. When made in the traditional manner, Irish stew is cooked so long that the individual ingredients break down, and the result is a very thick and hearty broth. Not everyone was pleased with Irish stew. Mark Twain in his American Claimant (1892) proclaimed that Irish stew was composed of leftovers. Lamb has become the predominant meat in Irish stew.