Line the base and sides of an 18cm (7") square x 4cm (1½") deep baking tin. In a small bowl, whisk the cream, yoghurt and egg, then put in the fridge to chill.

Put all the dry ingredients in the bowl of a food processor and pulse to combine. Add the butter, chives and lemon zest, and pulse seven or eight times, until the butter is about the size of small peas. Pour in the cream mixture and pulse again until the “crumbs” are moist but not quite coming together, then tip out on to a clean work surface and use your hands gently to flatten the mixture into a rough, 23cm (9")-long rectangle without compressing it too much. Sprinkle the feta and most of the cheddar evenly over the top and gently fold over the sides to bring the dough together into a round; don’t work it too much, because you want some of the feta to stay intact.

Now switch to a rolling pin. Gently roll out the dough into a roughly 18cm (7") circle about 2.5cm (1") thick, rotating the dough as you go. If it starts cracking around the edges, use the palm of one hand gently to squeeze it back together again and smooth out the cracks. Have ready a bowl of flour, to dip the cutter into between each stamp, which will ensure a clean cut. Using a 6cm plain round cutter, stamp out about four scones, then bring together the scraps, roll out and repeat – you should end up with nine scones in total and about 80g pastry left over – bake this separately for a cook’s treat. Arrange the scones in three rows of three in the lined tin and refrigerate for 30 minutes, to rest and firm up.

Ten minutes before you are ready to bake, heat the oven to 210C (200C fan)/425F. Brush the tops of the scones with the extra whipping cream, sprinkle over the reserved cheddar, and top that with the za’atar and sesame seeds. Bake for 15 minutes, rotate the tin, turn down the oven to 190C (180C fan)/390F and bake for another 10 minutes, until the scones are nicely browned and the middles spring back when lightly touched. Remove, leave to cool in the tin for five minutes, then carefully transfer to a cooling rack. Leave to cool for 10 minutes, then serve.