Preheat the oven to 180C/350F/gas mark 4 and finely chop all the herbs. Trim the roots of the spring onions and thinly slice them.
Drizzle a generous amount of olive oil into a large frying pan, fry the herbs and spring onions over a medium heat for a few minutes, then add the turmeric and cook for a further 5 minutes. Remove from the heat and set aside.
Mix the eggs, flour, yoghurt, baking powder, salt and pepper together until everything is well combined and smooth. Once the herb mixture has cooled slightly, slowly add a couple of spoonfuls at a time into the egg mixture and mix well, repeating until all the herbs are combined.
Add the barberries and walnuts and mix well.
Line a good sized ovenproof dish with baking paper and coat in olive oil. Pour in the egg and herb mixture, and bake for 35-40 minutes. It is ready when a knife inserted into the centre of the kuku comes out clean.
Cut into squares and serve with a green salad and perhaps some pickled radishes