How to Make It
Combine beef, bread crumbs, garlic, egg, 1/2 tsp. salt, chili powder, cumin and 2 Tbsp. water in a large bowl. Shape into about 18 1-inch balls.
Warm oil in a pot over medium-high heat. Working in batches, if necessary, brown meatballs on all sides, 3 to 4 minutes total (you don't have to cook them through).
Carefully add broth. Bring to a boil over high heat. Stir in carrots, zucchini, tomatoes and rice. Return to a boil, then cover, reduce heat to medium-low and simmer until rice and meatballs are cooked through, about 20 minutes. Season with salt, stir in cilantro and serve.