 The doughnut is popular in many countries and prepared in various forms as a sweet snack that can be homemade or purchased in bakeries, supermarkets, food stalls, and franchised specialty outlets.They are usually deep-fried from a flour dough, and typically either ring-shaped or without a hole and often filled.Doughnut shops have been described as common in Canada and as a "national institution", and doughnuts have been described as an "unofficial national food."