In a large soup pot melt oil over medium heat. Add the onion and garlic, stirring often and allow to soften, until translucent, about 7-8 minutes. Stir in the kale, broth, parsley, cilantro, and nutmeg and bring to a boil. Once it boils, reduce the heat and simmer, stirring occasionally, until greens are tender, about 10 minutes. Stir in lemon juice and season to taste with salt and pepper. Using a powerful blender, puree until smooth. If soup gets too thick, thin it out with leftover broth. This can be made one day in advance. Enjoy right away or cool and cover in the fridge.