I've found that vegan recipe threads get pretty good traction on hexbear. I don't think there are enough vegans on the fediverse to actually have a whole comm that's active enough to be worthwhile, but you can get quite a hopping thread going if you try.

I'd suggest posting to hexbear's c/food with a little detail about what kinds of recipes you're looking for. You'll likely get good engagement, especially if you respond to people responding to you, to make the thread stay active longer!

btw