Chocolate frangipane, shortbread and nut swirls

These biscuits are based on a method for biscotti eureka, but I have radically altered the recipe – it bears little resemblance to the original now other than the construction method and that it requires a shortbread-type biscuit and a frangipane-type filling. I have baked biscotti eureka a few times, and I find them delicious