Preheat the oven to 160 degrees Celsius or 325 degrees Fahrenheit and grease and line a 23cm springform cake tin with baking parchment.
Place the pineapple slices and 50 grams of the sugar into a large non-stick frying pan and cook gently for 4 to 5 minutes until caramelised. Set aside to cool.
Sift the flour, baking powder and salt into a large bowl and stir in the desiccated coconut and the remaining sugar. In a separate bowl, whisk together the egg yolk, eggs, melted butter, milk and vanilla until smooth.
Stir the mixture into the dry ingredients to make a smooth batter. Transfer a few spoonfuls of the batter into a separate bowl. Mix the pineapple slices with the larger amount of batter and pour into the lined tin.
Give the tin a tap to knock out any air bubbles then pour the reserved batter over the top. Bake for 40 to 45 minutes or until set with a slight wobble in the centre.
Transfer to a wire rack, leave to cool slightly then prick the surface all over with a toothpick or small skewer.
Meanwhile, cut the passion fruit in half and spoon the flesh into a small food processor. Pulse a few times to break down the pulp and loosen the seeds then pour into a bowl with the remaining ingredients.
Stir until the sugar has dissolved then spoon over the cake. Leave the cake to cool completely then cut into wedges and serve.