Create a double boiler. Add about 2 inches of water in a small saucepan and bring to a simmer. Add a larger saucepan to the top of the smaller saucepan.
Add the passion fruit pulp, lemon juice, salt, eggs, yolks, and sugar together on the top of the double boiler. Whisk the mixture well until fully combined.
Switch to a wooden spoon and stir the mixture continuously until the curd is visibly thickened, the curd should coat the wooden spoon and leave a streak when you run your finger over the curd.
Whisk in the butter and vanilla.
Strain the curd for any cooked egg. Pour into your jars. and cool.
If your curd dow not thicken, try turning up the heat on the double boiler and cooking for longer. If this does not help, try blooming a teaspoon of gelatin and stirring it into the curd while the curd it hot.
You can freeze the curd up to 3-6 months. Thaw in the refrigerator overnight before enjoying.