Mushy peas

Mushy peas are dried marrowfat peas which are first soaked overnight in water with baking soda, and then rinsed in fresh water, after which the peas are gathered in a saucepan, covered with water, and brought to a boil, and then simmered until the peas are softened. The mush is seasoned with salt and pepper. Throughout England and Republic of Ireland they are a traditional accompaniment to fish and chips. They are not a particularly traditional addition in this context in Scotland. In Northern England they are also commonly served as part of a popular snack called pie and peas (akin to the South Australian pie floater; but instead of the thick pea soup of the floater, in pie and peas it is mushy peas which accompany the meat pie) and are considered to be a part of traditional British cuisine. They are sometimes also packed into a ball, dipped in batter, deep-fried, and served as a pea fritter. Mushy peas can also be bought ready-prepared in tin cans.

Source: Wikipedia