1. Roll out the pastry on a floured surface and line a 23 or 24cm / 9 or 9½” tart tin. Prick the base of the tart with a fork and refrigerate for at least 30 minutes.
Preheat the oven to 190C / 375F
2. Place the tart shell on a baking sheet. Line the tart with parchment paper and fill it with dried beans. Bake until the pastry is just set, about 15 minutes. Remove the paper and beans and continue to cook until the pastry is a dark golden colour, 10 to 15 minutes. Transfer the tart to a wire rack and leave to cool completely.
1. Combine the sugar and butter in a deep, heavy saucepan over a medium heat. Stir to mix and cook, stirring occasionally, until the butter and sugar caramelize, 10 to 15 minutes. The sugar and butter will go through several stages. First it will look like a flour and butter roux, then it will appear curdled, and then the butter will leak out of the sugar mixture. Don’t worry: it will come together in the end.
2. While the caramel is cooking, pour the cream into a saucepan and bring to a boil over a medium heat. Remove from the heat and set aside.
3. Keep stirring the butter and sugar mixture, watching carefully as it begins to caramelize and remembering that the heat in the pan will continue to cook the caramel once it is removed from the burner. You want a rich, dark caramel colour, but you do not want to burn the mixture, which will give it a bitter taste.
4. When the caramel reaches the right colour, remove the pan from the heat and slowly and carefully pour in the cream; the mixture will bubble and spit. When the caramel stops bubbling, return it to a low heat and cook for 5 minutes, stirring to dissolve the caramel in the cream. Remove the pan from the heat and let the caramel cool for 10 minutes. Slowly pour the cooled caramel into the baked pastry shell and chill the tart for at least 2 hours.
This tart is easier to cut when it is chilled. Remove the tart from the pan and, using a wet knife, cut into wedges. Serve the tart at room temperature, however, for maximum flavour, with a dollop of whipped cream.