Can you grow onions from an onion?

[Durgan]

Onions, Onions, everywhere. They grow like weeds. Huge, juicy and all types. Put in the ground and they grow like Jack's beanstalk. I have taken to juicing\slurrying them. I like the slicers that don't burn, like Vidalia. Huge and sweet. Also Walla Walla.

 

[headfullofbees]

I like sweet, I like strong and pungent, I like onions that keep until the next crop is ready.
If any fail to, I want to be able to put them to best use.