Weigh the icing sugar and if mixing by hand, sieve into the bowl with the pistachios. If using a food processor, weigh straight into the processor bowl.
Mix the ground pistachios with the icing sugar using a firm wooden/silicone spoon or by giving a quick 'pulse' in a food processor.
Add the egg white and vanilla and mix together until even and well blended with the spoon, or for a few seconds in the food processor. The dough should now be a smooth, soft ball of marzipan. Adjust with additional nuts/egg white if too wet or dry.
Knead the marzipan with hands for a couple of minutes before wrapping in clingfilm.
Refrigerate until ready to use.
When ready to make the chocolates (or to use for another purpose), bring the marzipan to room temperature and gently knead. This will prevent cracking when rolled.
Place the marzipan on a large sheet of non-stick baking paper (dusted with icing sugar). Flatten slightly with the palm of your hand and then gently roll to the desired thickness using a rolling pin.
Cut the marzipan into shapes using small cookie cutters and set aside on baking paper (on a baking tray).
Place back in the fridge to firm up, until ready to coat with chocolate.
* Note: nutritional information is an estimate & may vary according to portion size/ingredient variants.Raw ground Pistachio nuts - you can grind in a blender/grinder on pulse until the even consistency of coarse sand. Be careful not to go too far or you will end up with pistachio butter.