Some of my most memorable one-on-ones have been a walk to get a coffee (or let’s be honest tea).
They are not planned, they are not structured and they start with a simple question – “How is it going?” or “What do you think of this?”.
You don’t need to make them a complex lunch, planning session, build-up that takes 1 hour.
Most times you’ll get more out of that relaxed 15 min discussion.