Un-roll the pastry sheet onto a lightly floured surface, mix the cocoa powder and icing sugar together. Use a sieve to sprinkle all over the pastry sheet, then fold in half like a book and chill for 15 mins. On a lightly floured surface, roll the pastry sheet into a slightly larger rectangle, big enough to line a 20cm tart tin. Line the tin, leaving any overhanging pastry – you'll trim this away once the tart is baked. Chill for 30 mins on a baking tray. Heat oven to 200C/180C fan/gas 6.

Line the pastry with greaseproof paper and fill with baking beans. Bake for 15-20 mins, then remove the paper and beans and bake for 15 mins more, until cooked through. Remove from the oven and leave the case to cool in its tin, then trim the sides.

While the pastry is cooling, make the date caramel. Warm the coconut milk until steaming, then pour 120ml of the coconut milk over the dates. Soak for 5 mins then tip into a food processor with the vanilla extract and a big pinch of flaky salt. Blitz until smooth. Spread the caramel onto the base of the tart and put in the fridge for 30 mins to set a little.

To make the ganache topping, heat the remaining coconut milk over a low heat until steaming. Put the chocolate and coconut oil in a large bowl and pour the warm coconut milk over the top. Leave to sit for a minute, then gently stir until combined. Spoon the mixture over the caramel and spread it out – don’t worry if the caramel comes up the sides a bit. Sprinkle with flaky sea salt and leave to set in the fridge for about an hour, then bring to room temperature before slicing and serving.