Ingredients
1/4 cup extra-virgin olive oil
1 large onion, chopped
6 large cloves garlic, 3 minced, 3 sliced
Coarse salt
1 1/2 teaspoons ground cumin
1/2 teaspoon ground cinnamon
1/2 cup panko breadcrumbs
1 1/4 cups low-sodium chicken broth
1 1/2 pounds ground beef
1 large egg, plus 3 large yolks
1/2 cup coarsely chopped fresh cilantro, plus more for serving
1 1/2 cups plain whole-milk yogurt
1 tablespoon cornstarch
Cooked rice, for serving
Ground sumac and red-pepper flakes, for serving
Preparation
In a large straight-sided skillet, heat 2 tablespoons oil over medium-high. Add onion, minced garlic, and 1 1/2 teaspoons salt; cook, stirring, until translucent, about 3 minutes. Add cumin and cinnamon and cook, stirring, about 1 minute more. Transfer mixture to the bowl of a food processor; process to a paste.
In a bowl, combine breadcrumbs and 1/4 cup broth; let stand 5 minutes. Add beef, onion paste, whole egg, and cilantro; mix with your hands to combine. With lightly dampened hands, form mixture into 28 balls, about 2 tablespoons each.
Heat remaining 2 tablespoons oil in skillet over medium-high. Working in batches (do not crowd pan), cook meatballs until browned on all sides, about 7 minutes a batch. Transfer to a plate; pour off fat from skillet. Return meatballs to pan; add 3/4 cup broth and sliced garlic. Bring to a boil, then cover, reduce heat to low, and simmer just until meatballs are cooked through, about 6 minutes. Transfer meatballs to a plate with a slotted spoon.
In a bowl, whisk together egg yolks and yogurt. In another bowl, whisk together cornstarch and remaining 1/4 cup broth; whisk into broth in skillet. Bring to a boil, whisking constantly, then strain through a sieve into yogurt mixture, stirring to combine. Return to skillet and cook over medium, stirring constantly, until just bubbling and thick enough to coat the back of a spoon, about 1 minute; season with salt. Add meatballs to sauce and heat through. Serve over rice, sprinkled with sumac, red-pepper flakes, and cilantro.
