Start by roasting the pistachios until fragrant. Let them cool.
In a food processor finely crush all the biscuits.
In a large bowl, add the crushed biscuits, pistachios and dried cranberries. Combine together.
Add the condensed milk and the rum, if desired. With your hands mix everything well together until you achieve a sticky mixture.
Roll this mixture in a cylindrical shape and then close together the edges to create a circle. Set aside for now.
Melt the chocolate and cover the dessert completely. Decorate with rosemary and pomegranates or cranberries to form a wreath.
Let the chocolate harden before slicing through it.