Heat the oven to 180C/160C fan/gas 4 and butter a deep baking dish (about 20 x 30cm and 5cm deep). Tip the flour, baking powder, sugar, lemon zest and a pinch of salt into a large bowl. Put the melted butter, milk, eggs and passion fruit pulp in a jug and whisk together. Pour the wet ingredients into the dry and mix together using a spatula until you have a smooth batter. Pour the batter into the prepared dish.

For the sauce, whisk the sugar, lemon juice, passion fruit pulp and lemon curd together in a heatproof bowl with 300ml boiling water from the kettle. Carefully pour the sauce directly over the batter in the dish, then bake for 40-45 mins until the top is set and golden, and the sauce is bubbling up at the edges. Serve warm with vanilla ice cream.