Heat oil in a pot over medium heat. Add the shallots, and sauté for 3 minutes. Then, add the garlic, ginger, and jalapeño pepper. Sauté for another 3 minutes then. Add the lemongrass, and sauté for another 1-2 minutes.
Add the vegetable stock, kefir lime leaves (if using), salt, broccoli, and potatoes. Bring to a boil. Lower the heat and cover with lid. Gently simmer, covered for 10-12 minutes.
Once vegetables are tender, take the pot off the heat. Add in the spinach and coriander. Blend with a hand-blender or in a food processor until very smooth.
Place the blended soup back in the pot, over low heat, stir in the coconut, add in sugar, and stir until warmed through. Do not boil.
Lastly, add the lime juice, and fish sauce to taste.
Divide between the bowls, and garnish with additional coriander leaves and roasted peanuts (optional).