Heat oil in a large stockpot over medium-high heat. Add onion and carrots and sauté for 5 minutes. Add garlic and keffir lime and sauté for 1 more minute.
Stir in the vegetable stock, lentils, corn, cumin, curry powder (plus saffron and cayenne, if using) until combined. Continue cooking until the soup reaches a simmer. Then cover and cook for 15 minutes, until the lentils are tender.
puree the soup until it reaches your desired consistency.
Stir in the lemon zest and juice until combined. season the soup with a generous pinch or two of fine sea salt and black pepper.
