Begin by making the pastry. Khorasan dough is more delicate than a plain flour dough and needs a longer rest time, so bear this in mind when beginning this recipe. Place the flour, salt and butter into a food processor and blitz to an even rubble. Slowly add the chilled water and keep blending until a dough forms (you may not need all the water)

Tip out onto a lightly floured surface and bring the dough together. Shape into a flat, round disc, wrap in clingfilm and rest in the fridge for at least 2 hours

Slice the courgettes into 3–5mm slices and toss with a pinch of salt. Leave to rest in a colander for about 10 minutes, then pat with kitchen roll to remove the excess moisture. This will help you achieve a nice, crisp pastry underneath

Slice the tomatoes to the same width as the courgettes and place in a colander or sieve set over a bowl. Sprinkle with leaves from 2 of the oregano sprigs, a pinch of flaky sea salt and the sherry vinegar. This will marinate the tomatoes, and the juices collected underneath make a tasty dressing for the rocket garnish. Leave the tomatoes to marinate for 5 minutes, then pat dry with kitchen roll before they start to go soggy

When the pastry has rested, carefully roll out between two sheets of greaseproof paper until 3mm thick. Trim into a 30cm circle and remove the trimmed excess. Preheat the oven to 180°C/gas mark 4

Remove the top piece of greaseproof paper and transfer the tart, along with the bottom sheet, to a large baking tray. Place the thin slices of feta on top of the pastry circle, leaving a 6cm border around the edge

Arrange the courgette and tomato over the top and then carefully begin to fold the edges of the pastry back in all around the edge

Sprinkle with olive oil, flaky sea salt and black pepper and bake for around 30 minutes

Remove from the oven and sprinkle over the remaining oregano leaves and lemon zest

This galette can be enjoyed hot or cold, and is especially good serves with a handful of rocket dressed with the reserved tomato dressing