Step 1

Heat the olive oil in a large pot over medium heat, and sauté the onion and celery until tender, about 8 minutes. Add in the garlic and sauté until fragrant, about one more minute. Add in the chopped potatoes, 4 cups of water or broth, and salt and bring the liquid to a boil. Once boiling, lower the heat and cover to let the vegetables simmer until the potatoes are fork-tender, about 20 minutes.

Step 2

Once the potatoes are tender, add the arugula to the pot and stir until bright green, about 3 minutes. Transfer the soup to a blender and blend until smooth, taking special care to vent the blender lid. (I like to cover the hole in the center of the lid with a thin dish towel so that the lid doesn't blow off from the steam pressure.) Blend in batches if you need to. Return the soup to the pot over medium heat and stir in the coconut milk, which adds a nice richness to the soup. Season with additional salt, if desired, and black pepper and serve warm with any garnishes you like. I added an extra dollop of coconut cream (the thick cream found in a chilled can of coconut milk) and some chopped green onions.