To make in a power blender (such as KitchenAid Artisan Power Plus, Vitamix or Froothie) after step one either sieve the cranberries or blend the cranberries until smooth. Then add the eggs and sugar and slowly turn blender up to full power (No 11) for 5 minutes. Then turn the blender down to No 6 and add the cubed butter a little at a time allowing each addition to get blended, then blend for a further 30 seconds. Pot up into sterilised jars.