2 lb [907 g] Yukon gold potatoes, peeled and cut into 3/4-in [2-cm] chunks
4 cups [1 L] chopped leeks, white and light green parts, thoroughly cleaned of all sand (about 4 leeks)
¼ cup [60 ml] extra-virgin olive oil
Kosher salt and freshly ground black pepper
3 cups [750 ml] baby arugula, lightly packed
½ cup [125 ml] dry white wine
7 cups [1.6 L] chicken stock
¼ cup [60 ml] heavy cream
¼ cup [60 ml] freshly grated Parmesan, plus extra for garnish
Crispy shallots (recipe follows – optional)
For the crispy shallots
1½ cups [375 ml] vegetable oil
3 tbsp [45 ml] unsalted butter
5 to 6 shallots, peeled and sliced into thin rings
Preheat the oven to 400°F [200°C].
Combine the potatoes and leeks on a baking sheet in a single layer. Add the olive oil, 1 tsp [5 ml] salt, and ½ tsp [2.5 ml]pepper and toss to coat the vegetables evenly. Roast for 40 to 45 minutes, turning them with a spatula a few times during cooking, until very tender. Add the arugula and toss to combine. Roast for 4 to 5 more minutes, until the arugula is wilted. Remove the pan from the oven and scrape roasted potatoes, leeks and arugula to a large pot set over medium heat. Add the white wine and chicken stock. Bring to a boil and simmer 5 minutes.
In batches, transfer the soup to a blender or a food processor, and puree the vegetables in batches until they’re all done. Transfer back to the pot, add the cream, 2 teaspoons salt, and 1 teaspoon pepper and check the seasoning.
When ready to serve, reheat the soup gently and whisk in ¼ cup of Parmesan. Serve hot with an extra grating of Parmesan and crispy shallots, if using.
To make the crispy shallots: Heat the oil and butter in a deep saucepan over medium-low heat until it reaches 220°F [105°C] on a candy thermometer.
Reduce the heat to low, add the shallots, and cook for 30 to 40 minutes, until they are a rich golden brown. The temperature should stay below 260°F [125°C]. Stir the shallots occasionally to make sure they brown evenly. Remove them from the oil with a slotted spoon, drain well, and spread out to cool on paper towels. Once they have dried and crisped, they can be stored at room temperature, covered, for several days.
Recipe Credit: Adapted from Ina Garten, Barefoot Contessa Back to Basics