Preheat the oven to 180°C/160°C fan/350°F/gas mark 4.
Place the biscuits in a food processor and blitz until very finely crushed. Alternatively, place them in a sealable freezer bag wrapped in a tea towel and bash them with a rolling pin.
Tip the crushed biscuits into a bowl and mix in the melted vegan butter. It should resemble wet sand.
Tip the biscuit mixture into a 23-25cm/9-10in loose bottomed tart tin and press it evenly across the base and up the sides. Use the base of a glass to pack it down really firmly.
Bake the base for 10 minutes then set aside to cool.
Cut the passion fruit in half and scrape the pulp into a food processor or blender. Pulse a few times to break it up. Press the pulp very firmly through a fine mesh sieve into a bowl to remove the seeds. Use the back of a spoon to press it through to extract as much juice as possible.
Measure the juice, you want 160ml (⅔ cup). If you don't have quite enough, add some lemon or lime juice.
Place the cornflour in a pan and gradually stir in the passion fruit juice, making sure there are no lumps.
Whisk in the condensed milk and coconut cream. Place the pan over a medium-low heat and whisk constantly until the mixture comes up to a boil and thickens.
Pour it into the prepared biscuit base and spread it level. Refrigerate for at least 4 hours, preferably overnight, until set.