There are two basic types of doughnut and variations in each type. The simplest to make are cake doughnuts, made from batter dropped into hot oil. The alternatives are yeast or risen doughnuts which are made from a dough in the same way as bread; these can be fried or sometimes baked.
Cake Doughnuts
These are made from a batter. They rise in the cooking process, so they are usually ring doughnuts, but can also be small 2cm balls. This is to ensure they are cooked through and achieve maximum rise. These are easy to make, all you need is the batter, some form of depositor and a fryer to drop the batter into to cook. The depositing can be by a handheld depositor or by a mechanical automated system. You can make them on demand, and serve them hot, or they can be cooled and decorated.
Yeast Doughnuts
These are made from dough, like bread. The dough is mixed, and divided into either balls or rings, then placed in a proofing oven to rise to the finished shape. Once proved the doughnuts are then cooked, usually fried, but they can be baked. These are made in advance and can be filled or decorated. These are the doughnuts you would find in a supermarket.
The quality of the doughnut will depend on how the dough is made, lots of varieties exist, just a simple sweet dough or something more luxurious like a buttery brioche.
