In a medium saucepan, combine the cranberries, water, and sugar. Cook over medium-high heat until boiling, then reduce to a gentle simmer for about 10 minutes.

Remove the pot from heat and let the mixture cool for 5-10 minutes.

Pour the mixture into a high-powered blender and blend for 1-2 minutes until smooth. If necessary, strain through a sieve for a finer texture.

Return the mixture to the pot, add the egg yolks, and whisk together.

Cook over medium heat while whisking for 5-10 minutes until the curd thickens and coats the back of a spoon.

Remove from heat and stir in the butter until melted.

Pour the curd into a sterile container, allow to cool, then cover and store in the fridge until ready to serve.