Tortilla Soup (without the tortillas)

1 tablespoon extra-virgin olive oil
1/2 medium red onion, finely chopped
3 garlic cloves, minced
1 teaspoon ground cumin
Pinch cayenne pepper
3 1/2 cups lower-sodium chicken broth
1 can (14.4 ounces) diced tomatoes, with juice
3/4 pound boneless, skinless chicken breasts, cut into 1/2" cubes
3 tablespoons fresh lime juice
Salt and freshly ground black pepper
1/4 cup chopped fresh cilantro

Instructions
In a medium saucepan, heat the oil over medium-low heat. Add the onion, garlic, cumin, and cayenne. Cook, stirring often, until the onion is softened, about 4 minutes.

Add the broth and tomatoes and their juice. Bring to a boil. Reduce the heat and simmer for 5 minutes. Add the chicken and return to a simmer. Cook until the chicken is cooked through, about 4 minutes.

Remove the pan from the heat and stir in the lime juice. Season with salt and pepper to taste. Ladle the soup into 4 bowls and sprinkle with the cilantro.