Step 1: In a large bowl, gently combine the ground beef, uncooked rice, egg, chopped fresh mint, minced garlic, finely chopped onion, salt, black pepper, and ground cumin. Mix just until everything is incorporated. Avoid overmixing, as this can make the meatballs tough.
Step 2: Roll the mixture into approximately 1-inch meatballs. You should get about 25-30 meatballs. Set them aside on a plate.
Step 3: Heat the olive oil in a large pot or Dutch oven over medium heat. Add the chopped onion and cook until softened and translucent, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant.
Step 4: Stir in the crushed tomatoes, chicken broth, water, and bay leaf. Bring the mixture to a gentle simmer. Season with salt and pepper to taste.
Step 5: Carefully add the meatballs to the simmering broth. Do not stir immediately, as this can break them apart. Let them cook undisturbed for about 5-7 minutes until they firm up slightly.
Step 6: Add the diced carrots and potatoes to the pot. Continue to simmer for 15-20 minutes, or until the vegetables are fork-tender and the meatballs are fully cooked through. The rice inside the meatballs will also be cooked.
Step 7: Stir in the diced zucchini during the last 5-7 minutes of cooking. Zucchini cooks quickly, and adding it later prevents it from becoming mushy. Taste and adjust seasonings as needed for your perfect albondigas soup recipe.
Step 8: Remove the bay leaf before serving. Ladle the hot soup into bowls and garnish with fresh cilantro and a squeeze of lime juice.