Combine cranberries, water, and orange juice in saucepan. Bring to a boil over medium-high heat then reduce heat to medium-low and cook cranberries for 8-10 minutes until the cranberries pop, burst, and are softened. Stir occasionally.

Cool cooked cranberries for 5-7 minutes then use an immersion blender to break down the cranberries further or, alternatively, transfer to a standard blender or food processor to purée the mixture. Transfer cranberry mixture to a fine mesh sieve positioned over a bowl and, using the back of a large spoon, gently press the cranberry purée through the sieve to strain the mixture. Discard any remaining solids.

As the cranberries are cooling, bring about 2” of water in the bottom of a double boiler to the simmering point (around 200°F – see Note below). Maintain the water at this simmering point over medium-low heat.

Off heat, place sugar in the top of the double boiler or heat-proof bowl. Mix in the orange zest.

Stir the strained cranberry mixture into the sugar.

In a small bowl, lightly beat the 3 egg yolks and the whole egg together with a fork, just enough to break up the yolks and blend them with the whole egg. Whisk the eggs into the sugar-cranberry mixture. Add the soft butter. Place this pot or bowl over the simmering water. Stir the mixture frequently as it cooks until it is thickened and the temperature of the mixture registers 175°F on a candy or instant read thermometer. Be patient as this will take awhile. Make sure the water in the bottom of the double boiler does not boil and stays only at the simmering point.

Remove curd from heat and strain through a mesh strainer a second time to remove any of the egg white that may have coagulated as well as the orange zest. Pour strained curd into sterilized bottle(s). Place a piece of plastic wrap directly on the surface of the curd to prevent it from forming a skin on top. Cool at room temperature. Remove plastic wrap. Cover jar tightly and refrigerate for up to 1 week.