Step 1Heat the oven to 400 degrees.
Step 2In a skillet, heat one tablespoon oil over medium heat and stir fry 1/2 cup barberries until they are shiny and slightly plump, 10 to 20 seconds, careful not to burn. Remove from heat and set aside to use later as a garnish.
Step 3In a mixing bowl, beat together the eggs, salt, pepper, flour, baking powder and advieh. Stir in the chopped parsley, cilantro, dill, fenugreek, green onions, garlic, lettuce, walnuts and remaining barberries.
Step 4Heat the remaining oil in an ovenproof baking dish in the preheated oven for 5 minutes.
Step 5Take the baking dish out of the oven and pour the egg mixture in the dish. Bake until set and lightly colored, 20 to 30 minutes. Remove and set aside for 5 minutes to give the kuku time to set up.
Step 6To serve, loosen the sides with a knife, cut to desired pieces and serve it in the baking dish or invert it onto a serving platter and cut into pieces to serve. Garnish with barberries.