Something I think most people are unaware of:
Runny and set honey are made from different types of nectar.
For example, rape (which is grown a lot where I live) will result in very hard setting honey. We had to be careful to extract the honey as soon as the comb was full or it would set in the cells and is then impossible to extract.
This is often not known because most runny honey will crystallise when stored somewhere too cold.
Set honey (such as that made from rape nectar) will need to be constantly stirred whilst it sets to avoid the crystals forming too big and causing it to be solid - just like ice-cream!
Disclaimer: I have no idea if this will give you the result you desire, but theoretically it should work.
As I said, most running honey will set if stored somewhere cold, therefore I would suggest you use an ice- cream maker to set your running honey, or refrigerate it - but be aware that you will need to stir it often to avoid the aforementioned issues.
You will then need to keep that honey somewhere cold to avoid it melting again. It's pretty cold here in the UK so a cupboard is usually cold enough.
References: Beekeeper for 6 years and long time honey and bee enthusiast!
Also just to note that there is no set line for which flowers produce set and runny honey it's a sliding scale - most store bought honey is just a big mix from different flowers. I believe it's something to do with how saturated with sugar the necar was.