First, sieve the flour and salt into a bowl, rub in the butter until mixture resembles bread crumbs. Gradually add the water to form a dough. Wrap in cling film and chill for 15 minutes.
Put the courgettes and salt into a sieve and leave to drain over a bowl for 30 minutes.
Roll out the pastry to line a 20cm flan tin, prick the base. Place a piece of baking parchment in the centre. Put on to a baking tray, and bake for 10 minutes. Remove the baking parchment; leave the flan to cool slightly.
Squeeze any remaining liquid from the courgettes. Put into a clean bowl with eggs, basil, garlic, grated nutmeg, cream, cheese and ricotta. Season and mix together.
Pour mixture into the flan case and bake for 30–40 minutes until golden brown.
Serve warm with some new potatoes and watercress salad.