Persian noodles (Reshteh) can be found in Middle Eastern markets or online. If unavailable, flat egg noodles or udon noodles are good substitutes.
Kashke (whey) is traditional but often hard to find. Sour cream, yogurt, or a mixture of milk and flour can be used as a substitute for the creamy garnish.
This soup tastes even better the next day as the flavors meld together. It freezes well; freeze without the noodles and add fresh noodles when reheating.
For a vegetarian version, omit the beef and use vegetable broth. The gheimeh can be made with extra yellow split peas and walnuts for texture.