Across the Middle East, yogurt is used to add creaminess to stews, soups and braises. Najmieh Batmanglij—who chronicles many of them in her book, “Cooking in Iran”—loves the way it adds tart, bright flavors to otherwise heavy dishes such as braised lamb with saffron and stewed spiced chickpeas.

Trouble is, yogurt curdles easily when heated. That's because the heat causes the milk proteins to form links, separating the curds from the whey and creating an unappealing, lumpy sauce.

But Batmanglij has an innovative way to preventing this. As a child in Iran, she recalled seeing women beat yogurt in clay pots with long wooden spoons before adding it to hot liquids. She takes an easier approach—whipping it in a blender or food processor for several minutes.

It turns out the blending keeps the yogurt liquified by breaking the proteins into smaller fragments, making them less likely to form enough links to create large clumps when heated.

Wondering whether the type of yogurt mattered, we tested her recipe for a yogurt-braised chicken with low-fat, full-fat and Greek-style. We found that blending helped prevent all varieties from curdling, but that the thinner (lower fat) the yogurt, the smoother the results.

Though the blender worked just as well, we favored the food processor because it was quieter. Low-fat and whole yogurts needed 1 to 2 minutes blending. Thicker Greek yogurt needed 4 to 5 minutes. Once blended, the yogurts remained stable even when added to recipes cooking at medium-high.