In a pot over medium heat, sauté olive oil, onions, garlic, and carrots until browned, about 6 to 7 minutes. Add lentils and sauté for an additional 2 to 3 minutes.
Pour in chicken broth and water. Bring to a boil, then lower the heat, cover, and simmer for 45 to 50 minutes until everything is soft. Use an immersion blender to blend until smooth.
Season with black pepper, turmeric, cumin, and salt to taste.
Serve in bowls with a squeeze of lemon and a sprinkle of red pepper flakes. Enjoy the soup warm with crispy bread or pita chips.