I opened my onion rack lately to find onions that had sprouted several-inch-long green roots... It made me extremely queasy and I threw them out. But I was wondering - would it be safe to eat them / cook with them?
Sure, but the rest of the onion gets mushy and unpalatable after they've grown for a bit. Some people eat the sprouts; they have a lot of protein, so they're popular with vegans and other protein challenged groups.
The roots aren't usually very green- they're white.
The part of the sprouts that is green is call... wait for it... Green onions.
You can just eat the sprouts and don't bother with the spent bulb.
Absolutely! They can be quite strong though. I would recommend cutting them thinly. I just used some as a garnish on my miso soup. They add just enough onion flavor and it looks nice.
When I lived in Belarus in the '90's, all the women had an onion sitting on top of a jar that had green sprouts, or "green" onions, and they cut from them continually. What I can't remember is how much water there was. I am trying it myself today as I found an onion had sprouted.
I love onion sprouts. They do not have as wild of a taste as the onion. Sometimes I only use the bulb to make sprouts.