Heat a soup pot over medium-high heat. Add the extra-virgin olive oil, 4 turns of the pan, the garlic, carrot, chile and shallot and cook until the mixture softens, about 2 to 3 minutes. Stir in the lentils and toss to coat in the oil, season with salt, to taste and curry spices or Ras el hanout. Add the stock and water to the soup and bring to a boil over medium heat. Reduce the heat and simmer until lentils are tender, about 40 minutes. Puree with an immersion blender into a smooth soup. Season with salt, if needed. Cool completely and store in the refrigerator for a make-ahead meal.
Reheat the soup over medium heat and stir in the fresh spinach until wilted. Heat the naan on a griddle pan with a few drops of water until crisp and hot on each side, then brush liberally with melted butter.