From 1906:
Not at all averse to sharing her precious secret of hash making, Maggie said that any person who had lived in Ireland knew how to make Irish hash. Nevertheless, as the following will prove, few Americans, Irish or otherwise, make it as she does.
According to her recipe, one puts into the pan a good sized lump of butter, and when the pan is hot, adds according to the members of the family, the desired quantity of finely chopped corned beef, and lets it heat. The original part comes in the treatment of the potatoes, which are freshly baked, scooped out from the skins while hot and added to the beef. The mixture is seasoned with salt, pepper, a dash of nutmeg, and a dash of onion juice, moistened with chicken broth or beef stock, and served piping hot. The concoction is simple and delicious. When President Roosevelt first tasted Maggie’s hash, he exclaimed, “By George! This is good.”