This is what I did last year, but with spring onions.
My kids like the YouTube channel "Slivki Show" which is quite popular in Germany, it is a Russian guy (?) I think that has a channel in German and one in Russian, with life hacks, recipes etc.
Here is a link to the
video where he shows how to do this with a bottle (starts about midway through the video):
I have been searching for a picture of the sprouted bottle but have not found it (yet).
ETA: The good thing is that you can start this in late winter (if you get the little onions already, that is) and then harvest 2-3 times when there is nothing growing in the garden yet.
I am only one, but still I am one. I cannot do everything, but still I can do something; and because I cannot do everything, I will not refuse to do something that I can do. (E.E.Hale)