The method for this extremely sweet, ultra-aromatic filling is a little unorthodox, but if you can suffer through a little stirring, it’s a snap. Start by rehydrating your raisins. Place them in a microwave-safe bowl and pour in water to cover. Zap them for 3-4 minutes until the water boils, then set them aside for half an hour. This, by the way, is a great technique anytime you want to add raisins that can actually be chewed easily to a filling.
While the raisins are steeping, beat the soft butter in a bowl, add the cardamom and beat everything together.
Add the warm cream and repeat.
Next comes the powdered sugar. Stir it in steadily. This mixture will be very stiff at first, but will shortly come together into a paste.
The paste will loosen up quite a bit when you finally add the drained raisins. In fact, since just a little water really loosens up anything that has powdered sugar in it, it’s a good idea to press the raisins while they’re in the strainer to get out as much residual moisture as you can. Add them in along with the chopped nuts and you’re ready to go!