Best way to display custom fields in posts?

I’m looking for a clean way to display a custom field within a post using a shortcode.

Sometimes I want to be able to put a sidebar box inside a post. Not a widget out in the sidebar, but something I can float right and flow text around.

I can do this by putting the sidebar text in a <div> tag but it would be easier if I could define a new custom field (“recipe_notes”) and put my content in that custom field and then call it in the post with [meta:recipe_notes]

Is that possible? I’ve looked around and I don’t see any obvious plugins.