Indeed, calling a meteor method is one option if you don’t need to observe changes of that document in real time. However I’m quite sure that if you subscribe to a separate publication which should fetch you a complete document, your minimongo should get updated. It’s a common use case.
There might be 2 problems
Check minimongo in meteor tools. If data is there, you should use tracker in your component.
Maybe your publication is incorrect. Even if you subscribe to a single document by id, you should return a cursor, meaning that you can’t use findOne.
Then maybe I didn’t/don’t understand what you’re asking. I tried to help solving the problem I believed you described here:
I was under the impression that you have a pubsub with limited fields and, in certain situations, you need instead a complete document. Had this been your problem, what I suggested would have solved it. Collection#findOne works perfectly fine in a method. But now it seems I don’t understand the problem.