Mmm, cardamom. I'm curious as to why crushing them rather than soaking them in the liquid and then removing them; is it merely a function of the time needed to soak, or is there a difference in flavor?

Me, I don't do fruity mincemeat, but I have been known to use blackberry jam in between two layers of a cake. Especially when the cake is chocolate. For an allspice/nutmeg-flavored cake, maybe apple butter or marmalade or even Nutella would be a good choice.