Behind the Recipes: Ash Reshteh

This category of hearty, porridge-like soups is mentioned in the oldest surviving Persian cookbook, from 1521, and its origins certainly date back even further—these dishes are so fundamental to Persian cuisine that the Farsi word for cooking, “ashpazi,” translates to “cooking ash.”

“Ash is an ancient dish, and I usually don’t use the word ancient,” Amir Sayadabdi, a Persian food scholar and anthropologist (and the translator of that 1521 cookbook), told me.

Taste a spoonful of ash reshteh, the most beloved and well-known type of ash, and it’s no surprise that these dishes have endured for centuries.

Earthy-hued from a combination of fragrant herbs and greens; thickened just enough to suspend ample legumes and reshteh (thin wheat noodles); and punched up by an array of tangy, fresh, sweet, and savory garnishes, ash reshteh is a wholesome, comforting soup tailor-made for nourishing loved ones. 

“You can’t do [ash reshteh] in small quantities,” Sylva Sedrakian, an Iranian home cook living in Watertown, Mass., told me. “It has to be shared.”

As is often the case with Persian recipes, every cook has their own way of making ash reshteh.

Broadly speaking, the process goes like this: Soak dried legumes overnight, simmer them in broth with caramelized onions and garlic, add lots of greens and herbs, and then add the noodles. Serve the bowls of ash topped with some combination of more caramelized onions and golden bits of garlic; thinned kashk (a fermented Persian dairy product); and oil spiked with cool, vegetal dried mint.

The foundation of the dish is the sweet, deeply browned onions.

Some cooks make them directly in the pot and then add the rest of the ingredients, but I decided to use a separate skillet and add the onions to the soup later: I’d need a skillet to make the other garnishes, anyway, and the lower sides and larger surface area of the pan would allow for better evaporation, speeding caramelization.

I sliced the alliums thin, then seasoned them with salt and a sprinkle of ground turmeric—its subtle earthiness and ochre hue is a hallmark of Persian cuisine—and watched as they slowly softened and turned deep golden brown.

As the onions caramelized, I decided on my legumes. Ash reshteh usually contains a few varieties, and nearly any kind of legume is acceptable, from navy beans to fava beans to split peas. Lentils were my first pick: They appear in most recipes for the dish, and I liked that some of the tiny pulses would break down and thicken the soup.

For the rest of the lineup, I wanted to use varieties of beans that I could easily find canned (a shortcut that many modern-day Persian cooks take), so I opted for chickpeas and red kidney beans, which both hold up well to long simmering.

I gave the dried lentils a head start by simmering them in a combination of broth and water for 15 minutes and then added the drained canned beans and simmered for another 15 minutes, allowing them to soften. 

As the lentils and beans cooked, I maximized time by making the rest of my garnishes in the skillet.

First, I simply sautéed some garlic and turmeric in oil until the garlic turned golden and then reserved both the alliums and the oil to bring delicate nuttiness and savor to each bowl.

Then, I added a second round of oil to the skillet and swirled in the dried mint. Woodsy and sweet, with a cooling undertone, this mint oil would add lively contrast to the earthy soup.

With that, all that was left to do for the toppings was to thin the concentrated jarred kashk with water. Salty, sour, and funky, this yogurt-based product is key to ash’s signature flavor. 

Once the lentils and beans were tender, I stirred in half of the caramelized onions and half of the browned garlic, saving the rest to top each bowl, and then it was time to incorporate the greens.

Spinach is a common choice, and the frozen, chopped type works great here; I just needed to give it a quick squeeze after thawing.

For the herbs, cooks use different combinations of classic Persian types: parsley, cilantro, dill, chives, scallions, and tareh (Persian leeks).

I opted for herbs that are easy to buy in large bunches: parsley, cilantro, and scallions (a close substitute for tareh). 

After a 30-minute simmer to break down the greens, I added the reshteh, breaking the noodles in half for easier eating (reshteh is slightly starchier than Italian pasta, but dried linguine is a close substitute). As the noodles softened, their starch further thickened the ash.

Once the noodles were tender, there was just one step left: allowing the ash to rest off the heat to thicken and mature in flavor. In Farsi, this concept is called “ja’oftadan,” which can be roughly translated as “to find its place”: After a long-cooked dish is finished, it shouldn’t be served until ja’oftadan, or until the dish has achieved the proper body and the flavors have settled.

It’s a concept backed by science—as liquid-y mixtures sit, soluble salty, umami, and tangy flavor compounds flow from areas of high concentration to areas of lower concentration, integrating the flavors of the components in the pot. 

Hard as it is to wait, I can tell you that your patience will be rewarded: There’s nothing more satisfying than ladling the cozy, warm ash into your bowl, garnishing it until it’s just right, and digging in.