Heat a big saucepan and toast the mustard seeds until they pop and become fragrant. Carefully remove the seeds from the pan and set aside.
Add the oil or ghee to the same pot, and when it’s hot, add the onions and curry leaves. Sauté until the onions are translucent while adding cloves, cardamom pods, crushed chilies, fenugreek and fennel seeds. When the mixture is tender and fragrant, add the carrots, lauki and coconut water and bring to a simmer. Add the grated ginger and garlic and minced Thai chilies, if using, and let simmer on low heat, covered, for around 15 minutes.
Add the kale or other greens, mushrooms, turmeric, coriander and cumin and stir until the flavors meld. Add salt and pepper, to taste.
Finally, add the reserved mustard seeds and green beans. Stir, cover, turn off the heat, and allow to steam until the green beans reach your preferred texture. Taste for salt and pepper and adjust accordingly. Allow to cool, then put in the fridge to be enjoyed the next day.
To serve, portion the curry into bowls and “dress” with 1 teaspoon of ghee per serving, chopped tomato, cilantro and a lemon wedge.