I use nextcloud cookbook but I would really love another or a federated alternative. It does its job but I don't think other people I know would use it.
I guess this doesn't qualify as self-hosted but I'm gonna comment anyway. I really like Pestle for iOS. I love the way it cuts the shit out of those 5,000,000 paragraph long introductions before the actual recipe and just grand the important parts. It's very handy.