Drain the borlotti beans and blend until you have a smooth pureé.
Break the chocolate into small pieces, place in a bowl and melt over a bain-marie. Place the cream in a saucepan, warm over a lower heat and add the saffron. Infuse for 3 minutes. Remove from the heat and leave to cool.
Mix the butter with the chocolate, then mix in the cream and the borlotti pureé. Refrigerate until firm.
Remove from the fridge and shape into truffles.
Sift the cocoa powder onto a plate. Roll the truffles through the cocoa powder to dust.
«Make sure the chocolate is completely melted over the bain marie before adding the butter. Try rolling your truffles through some chopped pistachos to add a little crunch.»