Its difficult to identify from a photo; its probably going to bolt(flower) as its overwintered. There would be some benefit to pot it up and then use the leafshoots as scallions before your spring onions are ready-April?
Against the possibility that its realy a shallot or clumping onion, you could plant it out.Presumably you know its source, which may determine.
If you’ve small people, they may enjoy growing it over a jamjar of water, seeing its roots and shoots develop.
