This is based on a classic Swiss chard tart from the South of France, known as tourte de blette, which is served as a dessert. Made slightly less sweet, it can also be served as a starter with a side salad. Traditionally it is covered with a pastry lid, making it more of a pie than a tart. My version omits the lid, because I rather like the rustic look of the filling. I have also added some crystallised melon, which seemed logical as the South of France produces superb crystallised fruits. We normally serve this with orange-flavoured crème fraîche but it is good with any citrus fruits or even a crystallised melon ice-cream. It makes a perfect finish to a light summer meal.
Roll out the pastry on a lightly floured work surface and use to line a buttered loose-bottomed tart tin, 22cm in diameter and 3-3.5cm deep. Chill for 40-50 minutes, then prick the base with a fork. Line the pastry case with baking parchment and fill with rice or baking beans. Place on a baking sheet in an oven preheated to 180°C/gas mark 4 and bake blind for 10-15 minutes, until very lightly coloured. Carefully remove the paper and beans, return the pastry case to the oven for 1-2 minutes to dry out the base, then set to one side.
Bring a large pan of water to the boil. Add the Swiss chard greens and blanch for 1 minute, then drain and refresh in cold water. Drain again and squeeze out as much water as possible. Shred the chard finely and set aside.
Lightly beat the eggs, then add the double cream, Parmesan and sugar and whisk until well combined. Place all the remaining, ingredients except the icing sugar in a bowl with the chard and mix together. Pour on the cream mixture and stir to combine. Place in the pastry case, arranging the ingredients quite rustically. Place in the oven at 180°C/gas mark 4 and cook for 30-40 minutes, until the custard is just set. Remove from the oven and leave to cool. Serve dusted with a little icing sugar.