Make the meatballs: Set a large Dutch oven or soup pot on the stove over medium heat so it is ready when the meatballs are shaped.

Make the meatballs: Put the ground lamb in a medium bowl. Add half of the chopped onion, half of the minced garlic, 1 teaspoon of the cumin, 1/2 teaspoon of the salt, and the black pepper.

Make the meatballs: Mix the lamb gently with your hands or a spoon until the seasonings are evenly worked in. Do not pack it hard, or the meatballs can turn dense.

Make the meatballs: Shape the lamb mixture into about 20 small meatballs, each about 1 inch wide. Set them on a plate.

Start the soup: Add the olive oil to the warm pot. Add the remaining chopped onion and the diced carrots.

Start the soup: Cook the onion and carrots over medium heat for 5 to 6 minutes, stirring a few times, until the onion looks soft and the carrots start to lose their raw edge.

Start the soup: Add the remaining garlic, the remaining 1 teaspoon cumin, and the remaining 1 teaspoon salt to the pot. Stir for 30 seconds, just until the garlic smells fragrant.

Simmer the lentils: Add the rinsed lentils and all 6 cups of broth to the pot. Stir well and raise the heat to medium-high to bring the soup to a boil.

Simmer the lentils: When the broth boils, lower the heat to maintain a gentle simmer. Cook for 15 minutes, stirring once or twice, until the lentils have started to soften but are not fully tender yet.

Add the chickpeas: Stir the drained chickpeas into the pot. Let the soup come back to a gentle simmer.

Cook the meatballs in the soup: Lower the meatballs into the simmering soup one at a time so they keep their shape. Make sure each one is mostly covered by broth.

Cook the meatballs in the soup: Simmer for 8 to 10 minutes, stirring very gently once near the end, until the meatballs are cooked through and the lentils are tender. The meatballs should look firm and no longer pink in the center if you cut one open.