STL export of a donut modeled in Andrew Price's "Blender for Beginners" tutorial YouTube series.  

The model prints without supports on FDM printers, but some of the overhangs are a bit aggressive and may require additional cleanup.  (Have not tried printing it on a resin machine, but I bet it would look great!)

For a “real life” donut size, the model should scaled so that it is approximately 80mm in diameter.