In a medium saucepan, combine the 2 cups of pitted prunes, 1 cup of water, 1/4 cup of orange juice, 1 teaspoon of orange zest, 1/4 teaspoon of salt, and 1/3 cup of brown sugar. Stir well to combine all the ingredients.
Place the saucepan over medium heat and bring the mixture to a gentle simmer. Stir occasionally to prevent sticking and ensure even cooking. Allow the mixture to simmer for about 10-15 minutes, or until the prunes are soft and the liquid has reduced slightly.
If you prefer a smoother consistency, transfer the mixture to a blender or food processor and blend until smooth. If you like a chunkier texture, you can skip this step and leave the filling as is.
Remove the filling from the heat and let it cool to room temperature. As it cools, the mixture will thicken up a bit more, making it perfect for filling your pastries.
Once cooled, transfer the prune filling to an airtight container and store it in the refrigerator. It will keep well for up to one week. You can also freeze it for longer storage; just thaw it in the refrigerator before using.
