This greens-based Persian version of a frittata is easy to make and lovely for a brunch or main dish. Traditionally, Persians serve it for Persian new year, Nowruz, and it is also served by Sephardic Jews.
Heat 2 tablespoons of the oil in a 10-inch pan with an oven-safe handle. (Cast iron pan is fine.) Cook the onion and leek or shallots for 10-12 minutes, stirring frequently, until they are transparent and soft, but not brown. Transfer them to a bowl and wipe out the pan.
In a large bowl, whisk together the eggs, salt, baking powder, pepper and turmeric if using. Add the chopped greens, onion/leek or onion/shallot mixture, and chopped nuts (if using) to the egg mixture and gently mix them together with a strong spatula. The mixture will be thick and green.
Heat the remaining 3 tablespoons of oil in the pan. Pour in the mixture and spread it out evenly. Cover the pan with a fitted cover or half sheet pan and cook on the stovetop over medium heat for about 8-10 minutes, until the bottom is set. While the egg mixture is cooking, turn on the broiler.
Uncover the pan and set it under the broiler for about 1 - 2 minutes, just until the top is set. Add the barberries or cranberries if using. Set the kuku sabzi aside for about 5 minutes to cool.
Run a sharp knife around the edges and slip the finished kuku sabzi onto a platter for serving, Consider serving yogurt alongside.
If you are using leeks, make sure to clean them well. I cut mine lengthwise in half, then half again (resulting in long strips), then sliced the strips into thin pieces and rinsed them in a colander. After rinsing, I dried them well before adding to the chopped onion and sautéeing them.
For the green herbs and greens, use whatever you have on hand. I suggest a mixture of cilantro, fresh dill, parsley (I prefer flat leaf, also called Italian, to curly leaf), and baby spinach. If you want to use up scallions, add them in too, maybe using slightly less onion or leek/shallots because scallions are sharp like those vegetables.
If you don't want to spend lots of time chopping and you're careful not to over-process, you can chop the greens together in a food processor. If using a food processor, do only about 8-10 quick pulses.