To make fresh passion fruit juice, cut the fruits in half and spoon into a fine-mesh sieve. When you have spooned out all the fruit, strain the pulp through the sieve and catch the juice in a pot. Add a 3/4 cup of water. The seeds should remain in the sieve. If you like your curd crunchy, you can also leave some seeds in. If you use store bought juice, pour it into a pot.
Mix the other ingredients except or the butter with a whisk in a small saucepan.
Cook over medium-low heat for 20 minutes, stirring constantly until thickened. If the curd is too thick, you can add up to another 1/2 cup of juice if needed to thin it out.
Take the pot off the heat and add the butter, stir it in until fully melted.
Pour hot passion fruit curd into a quart container or glasses with lid immediately. Let cool before refrigerating.
Notes
You can use fresh lilikoi juice or look for an organic juice with no added sugar - like Ceres.