In a saucepan, combine the cranberries, orange zest, 3/4 cup sugar, and water. Cook over medium heat until the cranberries burst and soften, about 10 minutes.
Remove from heat and blend the mixture until smooth. You can use a blender or an immersion blender for this step.
Strain the cranberry mixture through a fine-mesh sieve back into the saucepan to remove the skins and seeds.
Stir in the orange juice, eggs, egg yolks, butter, and salt. Work quickly as you do not want the eggs to cook during this process.
Cook the mixture over medium-low heat, stirring constantly, until it thickens and coats the back of a spoon, about 10 minutes. Do not let it boil.
Remove from heat and pour the cranberry curd into the prepared tart crust.
Bake the cranberry tart for another 10-12 minutes or until set and the curd has slightly darkened on top.
Once baked, allow the tart to come to room temperature then refrigerate for at least 2 hours to chill.
Once completely cooled and chilled, remove the tart from the pan, slice, and serve. Garnish with sugared cranberries, powdered sugar or fresh rosemary if desired. Enjoy!