Add the cranberries water and sugar to a pot over medium heat. Stir well and bring the mixture to a boil then reduce to a simmer and cook for about ten minutes until the cranberries have broken down and the mixture has thickened. Stir in the orange zest then let the mixture cool for five to ten minutes.

Use an immersion blender to blend until completely smooth. Add the egg yolks and return the pot to medium heat whisking continuously for 5 to 8 minutes until the curd is thick enough to coat the back of a spoon.

Remove from heat add the butter and stir until fully melted.

Transfer the curd to a heat safe container and let it cool completely. Store in the refrigerator for up to two weeks.