I’m looking into what would be involved in implementing a “recipe” card. Here’s my guess about how it might work:
Follow the example of existing cards to get the “Recipe” card to appear as an option
Build an HTML form which collects all the Recipe details
Store the recipe in the database using Mobiledoc with a new “Recipe” type and special “recipe” JSON data structure.
From reviewing the existing cards, it looks like there’s currently not one that injects content into the document as well as the body.
I did some more research into using Ghost for posting structured recipe content. I found no precedents for people doing this, but I confirmed that Wordpress absolutely dominates when it comes to recipe blogging. There are multiple fully-featured extensions for Wordpress.
With Ghost, there’s the extra hurdle that you have fork the project just to have custom card support. Three years ago a Ghost issue said that custom cards were on the “long term radar”. I don’t expect that foundational piece to appear any time soon.
If you just want to post a small number of recipes on Ghost with structured LD+JSON metadata, you could do that by using a tool which generates the metadata directly. Then copy/paste into the place on the post edit screen to inject code into the header. Here are two tools for that: