Heat the oven to 180C/fan 160C/gas 4. Whizz 100g pine nuts, sugar and marzipan to crumbs, add the lemon and egg whites and pulse, then add the flour and a pinch of salt and pulse to combine.
Roll the dough into 2cm balls and roll each in the whole pine nuts, pressing the nuts on. Space apart on a baking sheet lined with baking parchment. Bake for 20 minutes or until lightly browned and puffed.