To make the meatballs, preheat an oven to 375°F (190°C). Oil a baking sheet.

In a bowl, combine the coriander, cumin, curry powder, oregano, thyme, mustard, chili powder and salt. Add the ground lamb and tomato paste. Using your hands, mix gently but thoroughly. For each meatball, scoop up 1 tsp. of the mixture, form into a meatball and place on the prepared baking sheet. Bake until the meatballs are cooked through, about 10 minutes.

In a small saucepan over high heat, bring the water to a boil. Add the couscous, reduce the heat to low, cover and cook until all the liquid is absorbed, 8 to 10 minutes.

Meanwhile, in a large, heavy pot over medium-high heat, warm the olive oil. Add the shallots and garlic and cook, stirring constantly, for 1 minute. Add the broth and bring to a boil. Reduce the heat to low, add the meatballs and couscous and simmer for 10 minutes. Remove from the heat. Stir in the mint and season with salt and pepper. Ladle the soup into warmed bowls and serve immediately. Serves 4 to 6.