This is a perfect meal for a scorching early-summer day when spinach and garlic scapes are still plentiful. The creamy texture of coconut milk and pureed potato and the mellow sweetness of spinach pair nicely with the cooling, almost stringent taste of cilantro and tangy lime to make a decidedly light and refreshing soup . Use your favorite Thai-style curry powder or curry paste and make sure to adjust the salt level at the end of the cooking process so as not to over-season. To make a creamier, richer soup use regular coconut milk instead of light. I like to garnish with a healthy handful of cilantro leaves to really give the soup a bright, vibrant flavor. T —the preservery.
Heat butter in a large pot over medium-high until melted. Lower heat, slightly, and add onions. Saute until tender and lightly browned, about 8 minutes. Add garlic scapes and potatoes and cook until scapes are fragrant, about 1 minute. Add coconut milk, water, and curry powder and bring mixture to a boil. Reduce heat to low, cover, and simmer until potatoes are fork-tender, about 20 minutes.
Once potatoes are cooked, add spinach leaves and cilantro stems and stir until spinach is wilted and soft, about 5 minutes. Using an immersion blender (or a food processor, in two batches) puree soup until smooth and creamy. Season with salt and pepper, stir well, and remove from heat. Add lime juice and stir to combine. Serve soup hot with a handful of cilantro leaves in each bowl, to garnish.