This soup is worth a trip to an Asian grocer to find kaffir lime leaves, galangal and lemongrass; though you may come across them at a healthy foodie store if you’re lucky. Ginger can be substituted for the galangal, though its flavor is a bit softer, so you may need to add more. If you can’t find lime leaves, use an extra stalk or two of lemongrass. Regular basil can stand in for its Thai brethren. Give yourself time to let the soup cool before adding the cilantro and lime; this will keep the flavors fresh and the color bright.
Makes 6 servings
3 stalks lemongrass, chopped into 1” lengths
10 (1/4 inch thick) coins galangal (or ginger)
10 large kaffir lime leaves, lightly crushed
6 cups water
4 bushy sprigs thai basil, plus a few leaves for garnish
2 large bunches scallions, white and light green parts only, sliced
4 cobs of corn, peeled
1 1/2 tablespoons coconut oil
2 small serrano chiles, halved, seeds and ribs removed, finely chopped
1 teaspoon salt, more to taste
1 1/2 pounds small zucchini, trimmed and chopped
3/4 cup coconut milk, plus a few tablespoons for garnish
half a bunch of cilantro leaves, plus a few leaves for garnish
juice of 1-2 limes
Make the stock:
In a large saucepan, combine the lemongrass, galangal, kaffir lime leaves, and water. Bring to a boil, then cover and reduce to a bare simmer; simmer for 15 minutes. Remove from the heat, add the thai basil sprigs, then cover and steep for 10 minutes. Strain the stock, discarding the aromatics and reserving the stock.
Make the soup:
Meanwhile, soak the chopped scallions in cool water, swishing them a few times to dislodge any sandy dirt that can hang out in their crevices.
Meanwhile, prepare the corn. Stand a cob on its end in a shallow, wide bowl, and use a sharp paring knife to slice off the upper half of the kernels. Use the back of the knife to scrape the cob into the bowl as well. Repeat with the remaining cobs. Reserve one third of the kernels to finish the soup.
In a wide soup pot, melt the coconut oil over medium heat. Lift the scallions out of the water with your fingers, shake off excess water, and add to the pot along with the chopped serranos. Cook, stirring frequently, until the scallions are wilted and tender, 5 minutes. Add the zucchini, the two-thirds corn kernels and scrapings, 1 teaspoon salt, and enough stock to cover the vegetables. Bring the soup to a simmer and cook, partially covered, until the zucchini is tender but still bright green, about 15 minutes.
Let the soup cool to warm room temperature, about 30 minutes, stirring occasionally to release the steam. (this will preserve the bright color and flavor when you add the cilantro and lime). Add the cilantro leaves, and puree with a blender or immersion blender until very smooth. Blend in the coconut milk, and the juice of one lime. Taste, adding more lime or salt until the flavors taste bright.
Re-warm the soup gently over a low flame. Ladle into bowls, and top with the remaining corn kernels, a drizzle of coconut milk, and a few cilantro and basil leaves. Serve with additional lime wedges, if you desire.
I like this soup best within the first day or two, but extras will keep for up to a few days in the refrigerator.