Preheat the oven to 180°C. Grease and line a 20cm square baking tin.
Tip into a medium bowl and set aside for 5 minutes to cool slightly (start making the filling while you wait). Add the remaining ingredients to just combine, then tip into the lined baking tin. Use an offset spatula to smooth evenly into the base of the tin. Bake for approximately 15 minutes - until golden brown - while you make the filling.
When the base is golden brown, open the oven and pour the filling over the top of the base. Close the oven and reduce the oven temperature to 160°C. Bake until the filling is just set, approximately 15-20 minutes. Remove from the oven and set aside to cool completely, then refrigerate until cold.
Remove the cold passionfruit bars from the tin.