Mix the sugar, flour, passion fruit pulp, salt, and eggs in a medium pot until combined.
Slowly stir in the milk and heat on medium high heat, stirring continuously until it reaches a boil. This should take about 10-15 minutes.
Once the pudding reaches a boil, remove it from the heat and stir in the vanilla extract and butter. Stir until the butter is fully melted and both ingredients are combined.
Transfer pudding to small vessels and put in the fridge to cool! (I used 8 oz ramekins, but you do you. Jam jars also work great here.) Once it's nice and cool, enjoy!