(another demo) A doughnut (also spelled "donut"), is a sweet, deep-fried piece of dough or batter. The two most common types are the torus-shaped ring doughnut and the filled doughnut, a flattened sphere injected with jam, jelly, cream, custard, or other sweet filling. A small spherical piece of dough, originally made from the middle of a ring doughnut, may be cooked as a doughnut hole. Baked doughnuts are a variation that is baked in an oven instead of being deep fried.

Ring doughnuts are formed either by joining the ends of a long, skinny piece of dough into a ring or by using a doughnut cutter, which simultaneously cuts the outside and inside shape, leaving a doughnut-shaped piece of dough and a doughnut hole from dough removed from the center. This smaller piece of dough can be cooked or re-added to the batch to make more doughnuts. A disk-shaped doughnut can also be stretched and pinched into a torus until the center breaks to form a hole. Alternatively, a doughnut depositor can be used to place a circle of liquid dough directly into the fryer. Doughnuts can be made from a yeast-based dough for raised doughnuts or a special type of cake batter. Yeast-raised doughnuts contain about 25% oil by weight, whereas cake doughnuts' oil content is around 20%, but they have extra fat included in the batter before frying. Cake doughnuts are fried for about 90 seconds at approximately 190°C to 198°C, turning once. Yeast-raised doughnuts absorb more oil because they take longer to fry, about 150 seconds, at 182°C to 190°C. Cake doughnuts typically weigh between 24 g and 28 g, whereas yeast-raised doughnuts average 38g and are generally larger when finished.^{[citation needed]}

After being fried, ring doughnuts are often topped with a glaze (icing) or a powder such as cinnamon or sugar. Styles such as fritters and jelly doughnuts may be glazed and/or injected with jam or custard.

As well as being fried, doughnuts can be completely baked in an oven.These have a slightly different texture from the fried variety with a somewhat different taste due to the lack of absorbed oil—and so have a lower fat content.

There are many other specialized doughnut shapes such as old-fashioneds, bars or Long Johns (a rectangular shape), or with the dough twisted around itself before cooking. In the northeast USA, bars and twists are usually referred to as crullers. Doughnut holes are small spheres that are made from the dough taken from the center of ring doughnuts or made to look as if they are. These holes are also known by brand names, such as Dunkin Donuts' Munchkins and Tim Hortons' Timbits.