A potato-based doughnut traditionally called a spudnut is known as a spudnut.
Spudnuts are doughnuts made with mashed potatoes or potato flour. The potato contributes moisture and a distinctive texture, while the dough is still commonly sweetened, leavened, shaped, and fried like other doughnuts. They may be glazed, sugared, or filled depending on the recipe.
The term became especially associated with American commercial doughnut shops during the twentieth century. The Spudnut Shops chain was founded by brothers Bob and Al Pelton, who promoted a potato-based doughnut mix and expanded the brand through franchising. Many independent bakeries also used the name.
A spudnut is not simply a fried potato cake. The defining feature is its use in doughnut dough. Recipes differ in whether they use leftover mashed potatoes, dehydrated potato flakes, or potato flour, so texture and flavor vary. The name is a blend of “spud,” an informal word for potato, and “doughnut.”