In a large bowl, combine eggs, spinach, scallions, herbs, walnuts, turmeric, salt and pepper. Mix well. Heat oil over medium heat in 10-inch skillet. Add egg mixture and cook until it begins to set about 5 minutes. Reduce heat to low, cover and cook until completely set about 15 minutes. Cut omelet into 8 wedges with a spatula, while still over heat in pan. Carefully turn each wedge and cook, covered, 5 minutes more. Transfer to serving plate and serve.