A question about a recipe: Buttermilk Vinaigrette

I chop, run through a blender/food processor, and then strain through cheesecloth or a strainer. Voila!

Ah-ha! Many thanks for the quick and helpful reply.

Yes -- if you grate an onion on a box grater and then press the pulp through a small sieve, you'll get onion juice. When I'm feeling lazy, I just press the pulp in my hands to get out the juice. Although then I have to wash my hands *really* well to get rid of the onion smell!

Here's a LOT of detail about onion juice - a fascinating read, actually! http://markbittman.com/remembering-onion-juice