I brought a handful of Jerusalem Artichokes home from the market, washed and roasted them (skin and all) in the oven with a simple drizzle of olive oil, sea salt, and pepper. I cooked them all the way through as I would a baked potato. I tried roasting them a second time replacing the olive oil with hazelnut oil for even tastier results. Now, the vegetable risks to take over my produce life as I know it! I cut some into thin rounds, fried them and sprinkled them over an arugula salad. Delicious. I thought I had reached my peak with these preparations until I tasted this soup...The combination of roasting and stewing them yields a complex flavor.
Preheat the oven to 450 degrees F.
Place 1/2 the Jerusalem artichokes on a baking sheet. Drizzle them with 1 1/2 tablespoons olive oil and sprinkle with salt and pepper. Place the tray in the center of the oven and cook until they are completely yielding when pierced with the tip of a knife, 30 to 45 minutes.
Meanwhile, slice the rest of the Jerusalem artichokes in 1/2-inch thick slices. Heat a medium pot and add the remaining 1 1/2 tablespoons olive oil. Add the onion and garlic and season with salt and pepper. Cook for 5 minutes. Add the thyme and the Jerusalem artichokes slices and stir to blend the ingredients. Check the seasoning. Cook for 5 to 10 minutes and add 4 cups water.
Cook until the Jerusalem artichokes are completely tender, 25 to 30 minutes. If the liquid reduces too much during this cooking time, add the remaining 1 cup water. Remove the roasted ones from the oven, quarter them and add them directly to the soup mixture. Taste for seasoning.
Remove the thyme from the pot. Add the cream. Puree the soup in small batches in the blender (or a hand blender) until smooth. For a more "rustic" texture, puree only 1/2 and leaving the other 1/2 "chunky." Serve with crusty sourdough or a seeded bread to bring out the naturally nutty flavor of the soup.
Serving suggestion: Crusty sourdough bread or seeded bread.