1. caramelize mirepoix in a pan (go slow to get nice caramelization to get some sweetness) go kind of heavy on some shallots
2. deglaze with bourbon (don't use anything too high-end as once you burn off the alcohol many of the nuances will be lost, but don't use swill either)
3. next deglaze with hard cider (a dried style such as Blackthorn)
4. Add some cider and reduce to a syrup
5. add demi and reduce
6. finally finish off with heavy cream and season (I find the richness of the cream helps to smooth out the rough edges of the bourbon and at the same time accents it).
7. season with salt and pepper and strain
At this point you could add some apple (dried or fresh) to give you some chunkies in your sauce, but I would just keep it smooth