TEHRAN - For many Iranians, Ash Reshteh (Persian greens, bean and noodle soup) is a sign of the arrival of spring. The thick soup is served during the festivities leading up to Noruz, the Persian New Year, which usually falls on March 20.

The flavor of this beautifully spiced vegetable soup is mainly characterized by two uniquely ingredients: the first one is Reshteh, or flat noodles, which are starchier and saltier than their Italian counterparts, and as they cook, the starch they release thickens the soup.

And the second is kashk, a form of dried, drained yogurt or whey, which is saltier and sourer than Greek yogurt or sour cream. More like feta than yogurt, kashk gives ash its distinct, satisfying flavor.

Ingredients (Yield: serves 6-8)

1⁄2 cup canola oil

2 onions, thinly sliced

1⁄2 cup each dried kidney and cannellini beans, chickpeas, soaked overnight, drained

1 1⁄2 tbsp. ground turmeric

Kosher salt and freshly ground black pepper, to taste

6 cups chopped spinach

1 cup chopped parsley

1⁄2 cup brown lentils

1 bunch chives, finely chopped

2 cups reshteh or dried linguini

8 cloves garlic, thinly sliced

2 tbsp. dried mint

1⁄4 cup powdered whey (optional; see recipe, mixed with 4 tbsp. water)

Recipe

Heat 1⁄4 cup oil in an 8-qt. saucepan over medium-high heat. Add onions, and cook until caramelized, about 20 minutes. Transfer half the onions to a bowl; set aside for garnish. Add all beans, turmeric, and salt and pepper to onions in pan; cook, stirring, for 5 minutes. Add 12 cups water; bring to a boil. Reduce heat to medium-low; cook, covered, until beans are barely tender, about 50 minutes. Add spinach, parsley, lentils, and chives; cook for 20 minutes. Add noodles, and cook until noodles and beans are tender, about 12 minutes more.

Meanwhile, heat remaining oil in a 10" skillet over medium-high heat. Add garlic; cook until lightly browned and crisp, about 3 minutes. Using a slotted spoon, transfer to paper towels to drain. Return skillet to heat and add mint; cook until fragrant, about 1 minute. Ladle soup into bowls; top with reserved caramelized onions and garlic chips, then drizzle with the mint oil and whey.

AFM/MG