Bring the cream and butter just to a simmer in a saucepan over moderate heat. Remove from heat, then add chocolate and jam if that's what you're using and stir gently with a heatproof rubber spatula until ganache is smooth. Now stir in framboise if you’ve decided on adding alcohol.

Pour into a bowl, cover and chill the ganache mixture for 2-3 hours or until firm.

Remove the ganache from the fridge and roll into 25 balls. When you’re ready to coat them simply pour the freeze dried raspberry powder into a shallow bowl or dish and sprinkle over the caster sugar. (If you're using pistachios mix them with the raspberry powder) Drop two or three truffles onto the powder and shake the dish to and fro, proceed with the remainder. Chill on a tray until needed.