Persian Herb Frittata (Kuku Sabzi / کوکو سبزی)

1. Prepare Herbs: Wash and thoroughly dry all the fresh herbs. This is crucial to prevent a watery kuku. Finely chop the parsley, cilantro, dill, and chives (or scallions). You can do this by hand or in a food processor (pulse briefly to avoid mushing). You should have about 3-3.5 cups of chopped herbs in total.

2. Prepare Add-ins (Optional): If using walnuts, roughly chop them. If using barberries, rinse them under cold water and pat dry. Set aside.

3. Combine Ingredients: In a large bowl, crack the 6 eggs. Whisk them well with a fork until thoroughly combined. Add the chopped herbs, chopped walnuts (if using), rinsed barberries (if using), flour (if using), baking powder (if using), turmeric powder, salt, and black pepper. Mix everything gently until just combined. Be careful not to overmix, as this can make the kuku tough.

4. Cook on Stovetop: Heat 2-3 tablespoons of vegetable oil or olive oil in a large (10-inch or 25cm) non-stick skillet with a tight-fitting lid over medium-low heat. The oil should cover the bottom of the pan.

Once the oil is hot (it should shimmer), pour the egg and herb mixture into the skillet. Spread it evenly. Reduce the heat to low, cover the skillet tightly with the lid, and cook for 15-20 minutes. This slow cooking allows the kuku to cook through and become golden brown on the bottom without burning.

5. Flip or Finish in Oven: After 15-20 minutes, check the bottom. If it's golden brown and the edges are set (the top might still be slightly jiggly), you have two options:

- Flip Method: Carefully invert the kuku onto a large plate, then slide it back into the skillet cooked-side up. Cook, covered, for another 10-15 minutes, or until the second side is also golden brown and cooked through.

- Oven Finish Method (easier for beginners): If your skillet is oven-safe, transfer the skillet (uncovered) to a preheated oven at 180°C (350°F) and bake for 10-15 minutes, or until the kuku is fully set in the center and lightly golden on top.

6. Serve: Once cooked, slide the Kuku Sabzi onto a cutting board. Cut into wedges or squares. Kuku Sabzi is traditionally served with yogurt (plain or mixed with garlic/mint), fresh bread (like lavash or sangak), and often tomatoes or pickles. It can be served warm or at room temperature.

Note: For a richer kuku, you can add 1/4 teaspoon of saffron threads steeped in 1 tablespoon of hot water to the egg mixture.