Sunchokes have the soft freshness of artichoke hearts with the earthiness of root vegetables—perfect for simmering with leeks and blending with butter for a rich, velvety soup. Plus, a finishing drizzle of ginger oil adds a nice kick!
Soup: Roughly chop dark green leek stalks. In a heavy-bottomed pot over medium-low heat, melt 3 tablespoons butter; then add leeks. Smash and peel garlic cloves and add them to the pot. (If you're using a Vitamix to pureé the soup later, you can leave garlic skins on.) Continue to cook leeks and garlic until soft, stirring occasionally, 2–3 minutes. Meanwhile, in a small saucepan over low heat, warm the water or stock.
Roughly chop unpeeled sunchokes to a uniform size, about 1-inch pieces. Set aside. Meanwhile, tilt the pot with the leeks to pool the butter. Place bay leaves on top of the butter so they lightly fry for about 5 seconds. Then stir and continue sautéing until there is less popping coming from the pot, 2–3 more minutes.
Ginger Oil: Slice unpeeled ginger into coins. Place in skillet over medium-high heat along with the oil. Heat until the ginger begins to fry, 2–3 minutes; fry for 1 minute, then turn off heat and set aside to cool. Once cool, store ginger and oil in a jar with a tight-fitting lid. (Ginger Oil can be made in advance; it will keep in jar, refrigerated, for two months.)When leeks are melted, remove from heat and season with a pinch of salt and stir. To the pot, add sunchokes and the warm water or stock. Turn heat to low and bring to a simmer. Once simmering, cook uncovered until the sunchokes are soft, 25–45 minutes. (Cooking time will depend on the freshness and water content of the sunchokes.)
When the sunchokes are soft and break apart, discard the bay leaves before adding the contents of the pot to a blender. (If you’re using a high-speed blender such as Vitamix, you can leave the bay leaves in.) Replace the lid and blend on low speed to combine the ingredients; then slowly increase the blender speed to medium for 30 seconds. Turn speed back to low, remove the cap, and add the butter one piece at a time, so it emulsifies into the soup. When all of the butter has been emulsified, place the cap back on and purée at high speed for 30 seconds. (Optional: Pour soup through a fine-mesh strainer or chinois back into the pot for a more refined texture.)
Assembly: Taste soup and adjust seasoning. Ladle warm soup into bowls. Drizzle a spoonful of Ginger Oil on top and serve.