Preheat the oven to 180°C.

To make the pastry, add all the ingredients to a blender and blitz until it comes together to create a dough. Wrap it with plastic, knead slowly to form a disc and refrigerate for 30 minutes. Between two sheets of baking paper, roll the dough into a circle about 2cm larger than the Le Creuset Fluted Flan Dish. Push the pastry into the case, trim the edges and chill before baking. Prick the dough with a fork, line with baking paper and fill with dry beans, and bake for 15 minutes until lightly golden. Remove the beans and paper. Return to the oven for another 10 to 15 minutes.

Allow to cool before making the caramel. Add the sugar and water in a small Le Creuset Saucepan over medium-high heat, and cook without stirring until the sugar dissolves and gains a caramel colour. Remove the pan from the heat and add the cream. It will bubble a little bit. Cook for about 1 or 2 minutes, stirring constantly with a wooden spoon until smooth. Remove from the heat and add the butter and salt flakes. Stir well until smooth. Let the caramel cool slightly and pour over the crust. Chill until the caramel has set.

For the chocolate ganache, heat the cream in a small Le Creuset Saucepan. As it begins to boil at the edges, pour over the chopped chocolate. Let sit for one minute, then stir until smooth. Pour the chocolate ganache over the layer of caramel. Spread it evenly and chill to set before serving. Sprinkle with sea salt flakes and serve.