Place all the ingredients for the pastry base in a bowl and quickly knead till smooth. Wrap in cling film and refrigerate for 1 hour .
In the meantime cut courgette in half length wise and cut into small strips, omit the seeds and discard them. Heat butter in a frying pan and fry courgette till they start to soften. Season with Herbes de Provence, salt and pepper and let cool.
Preheat your oven to 190 C / Gas 5. Grease a springform tin or line with greaseproof paper.
On a lightly floured work surface roll out the pastry slightly larger than the bottom of the springform tin. Fit the pastry into the tin. Cover with greaseproof paper and dried beans and bake in the preheated oven for 20 minutes. Remove beans and paper.
Separate the eggs, Beat egg whites till stiff. In another bowl beat egg yolks, soured cream and Parmesan, at the end stir in the feta cheese. Season with salt, pepper and herbes de Provence. Fold in courgette and egg whites and spread evenly over the pastry base.
Bake in the oven till the top is lightly brown, 20 minutes.