In a mixing bowl add the flour and paprika and rub together with the butter until crumbly, mix in the grated cheese and a few drops of cold water to bring together into a dough. Roll the dough in a log shape 2 inches in diameter and chill for 2 hours until firm wrapped in cling film.
Heat the oven to 190C/170C fan/gas Remove the dough from the fridge brush the dough with a little milk or water and roll in the sesame and nigella seeds. Slice the dough 1/4 of an inch thick and bake on a baking sheet lined with parchment paper spaced an inch apart.
Bake for 16-18 minutes until crisp and golden. Allow to cool and store in an airtight container for 2-3 days.