In a very large enameled cast-iron casserole, heat the oil. Add the garlic cloves and cook over moderately high heat until sizzling, about 2 minutes. Add the shallots and cook over moderate heat, stirring until softened, about 3 minutes. Add the chiles and curry leaves and cook for 2 minutes. Add the ginger and lime leaves and cook for 2 minutes. Add the fennel, carrots and curry powder and season lightly with salt. Cover and cook, stirring occasionally, until the vegetables begin to soften, about 5 minutes. Add the coconut milk and bring to a boil. Cover and cook over low heat, stirring a few times, until the carrots are tender, about 10 minutes longer.