You might try a vanilla bean, split & scraped. Or you might try adding a pound of LME, or even some fruit(s) like raisins, dates, figs. I've "dry-hopped" with sachets of caraway seed, I think caraway goes with apple like butter goes with bread. I like to use a heaping tablespoon of caraway seed in 6 gallons of cider, I usually leave it in for 2 or 3 weeks, but I've left in longer too, for more caraway flavour. You could also add a bit of wine tannin if you wanted.
Regards, GF.