While frying or baking a donut does not take a lot of time, the dough of the donut takes some time to prepare. For a yeast-based dough, at least an hour and a half are required for the dough to double in size. Shaped donuts have to rise for an additional 45 minutes. The dough for cake donuts needs to be chilled for at least two hours so that the sugar absorbs the liquid from other ingredients. Once your dough is prepared, it only takes 2 to 3 minutes to fry each donut. You can fry them three or four at a time.