Parmesan shortbread

I ate about 10,000 of these at a wedding reception last year, and resolved to make them myself. I googled the recipe and found it on Nigella Lawson's site, so here's my take on her recipe.

Ingredients
  • 150g of plain flour
  • 100g of unsalted butter
  • Half a teaspoon of cayenne pepper
  • 75g of parmesan cheese
  • 1 egg yolk
Method
  1. Preheat the oven to 180°C.
  2. Sift the flour and cayenne pepper into a mixing bowl.
  3. Cut the butter into little chunks and add it to the bowl.
  4. Rub the butter into the flour mixture with your fingers until you have something like breadcrumbs.
  5. Grate the parmesan (or open the packet if you've bought ready-grated).
  6. Stir the grated parmesan into floury-buttery mixture.
  7. Separate the yolk from the eggwhite and stir the yolk into the mixture.
  8. Knead together gently with your hands until you have a lump of soft, but not sticky, dough.
  9. Lay some clingfilm out on a surface. Place the ball of dough on it.
  10. Roll the dough into a long sausage about three inches thick. Pat the ends so that they're flat.
  11. Wrap the clingfilm around the dough and twist the ends like a Christmas cracker.
  12. Place the wrapped dough in the fridge for at least 45 minutes.
  13. Put a sheet of baking parchment over a baking tray.
  14. Take the dough out of the fridge and cut it into medallions, about a centimeter and a half thick (I realise I'm mixing imperial and metric measurements here. Whichever cap fits, wear it, I say).
  15. Place the biscuits on the baking tray and bake for 15 to 20 minutes until irresistable.