Pre-heat the oven to 160°C (fan) / 180°C (conventional) / Gas Mark 4.
Take a 12-hole muffin tin, grease (using 1 tbsp of olive oil) and line the holes with baking paper. Brush a little olive oil into each recess after lining and leave to one side until you are ready to use.
Put the herbs, spring onion ends, spinach, eggs, turmeric, garlic, lime zest, olive oil, self-raising flour, salt and pepper into a food processor and blitz until the herbs are finely chopped.
Add the barberries (if using) to the mixture and stir.
Take the muffin tin and spoon the mixture evenly between the 12 holes.
Place in the oven for 25 mins. To check if the kuku are done, use a thin skewer / tip of a knife to check one by gently poking to the bottom. It should come out clean.
Serve warm or cold sprinkled with ground walnuts alongside a salad, dips and bread as part of a mezze-style meal.