Put the flour into a bowl with a pinch of salt. Add the butter and rub in using your fingertips until it resembles breadcrumbs.

Add egg yolk, form and transfer to a greased baking tray. Spread the dough evenly, make sure there is some on the sides. Poke holes into the dough using a fork.

Bake for 20mins in 200C/390F. Let cool for a few minutes. In the meantime slice the zucchini, and grill it till soft.

Spread yoghurt on the tart, put the grilled zucchini on top, sprinkle with feta cheese, and then with some herbs.

Bake for additional 10-15mins in 160C/320F. Serve hot.