Combine broth, beans, garlic, turmeric and cumin in large saucepan, bring to a boil. Reduce heat and simmer 15 minutes. Whisk eggs and lemon juice until well-blended.

Gradually whisk 2 cups soup into egg mixture. Return to saucepan. Stir over medium-low heat until heated through, about 5 minutes. (Do not boil.) Add cayenne. Season with salt. Ladle into bowls, sprinkle with mint.