I didn't know potato soup could be elevated to such a high place. This version is without a doubt the most flavorful, complex, restaurant quality one that I've made. It does require a few extra steps, such as roasting the potato and leeks in the oven before pureeing and finishing it off, but trust me, it's simple and well worth it. It does take some time though, so make sure you start dinner at least an hour before you want to serve. Then, as the potatoes are roasting measure out all the other ingredients so they are ready to go when you are. I don't know about you but I hate having to stop and grate 1/4 cup of cheese while my soup is bubbling away waiting for me to hurry up already. You can also make the optional fried shallots to garnish while the potatoes are roasting. If you prepare ahead of time, you can be done in just over an hour from start to finish. Most of that time is to allow the potatoes to cook through.
This soup calls for a strange ingredient as far as potato soup is concerned: arugula. I'm not sure why, other than it adds pretty little green flecks throughout, that people will probably mistake for leeks. It does look gorgeous, while adding to the nutritional value so I always use it. You can't taste it at all, and like I said, people will take them for leeks so if you need to sneak some veggies into certain people in your family this is an ingenious way! Win-win!
Roasted Potato Leek Soup
adapted from Barefoot Contessa Back to Basics
serves 6 to 8
2 pounds Yukon Gold potatoes, peeled and cut into 3/4-inch chunks
4 cups chopped leeks, white and light green parts, cleaned of all sand (4 leeks)
1/4 cup good olive oil
Kosher salt and freshly ground pepper
3 cups baby arugula, lightly packed
1/2 cup dry white wine, plus extra for serving
6 to 7 cups chicken stock
3/4 cup heavy cream
8 ounces creme fraiche (or sour cream)
1/4 cup freshly grated parmesan cheese, plus extra for garnish
Crispy shallots, optional, for garnish (recipe to follow)
Preheat the oven to 400 degrees
Combine the potatoes and leeks on a sheet pan in a single layer. Add the olive oil, 1 teaspoon salt, and 1/2 teaspoon 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 place over two burners. Stir in the wine and 1 cup of the chicken stock and cook over low heat, scraping up any crispy roasted bits sticking to the pan.
in batches, transfer the roasted vegetables to a food processor (*see note) fitted with the steel blade, adding the pan liquid and about 5 cups of the chicken stock to make a puree. Pour the puree into a large pot or Dutch oven. Continue to puree the vegetables in batches until they're all done and combined in the large pot. Add enough of the remaining 1 to 2 cups of stock to make a thick soup. Add the cream, creme fraiche (or sour cream), 2 teaspoons salt, and 1 teaspoon pepper and check the seasonings.
When ready to serve, reheat the soup gently and whisk in 2 tablespoons white wine and the parmesan cheese. Serve hot with an extra grating of parmesan cheese and crispy shallots, if using.
* be sure to use a food processor to blend the soup. If you use a blender it will cause the potatoes to get gummy. They are fickle things!
1 1/2 cups olive oil or vegetable oil
3 tablespoons unsalted butter
5 to 6 shallots, peeled and sliced into thin rings
Heat the oil and butter in a saucepan over medium-low heat until it reaches 220 degrees on a candy thermometer (or until hot)
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 degrees. 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 fried and crisped, they can be stored at room temperature, covered for several days, if not using right away.
So, the recipe calls for creme fraiche, as you can see, but I have made it both that way and using sour cream to substitute. There is no big difference, so use the sour cream if budget is a concern to you (and who isn't it a concern to?) But, there's no doubt that creme fraiche is special so use that if you are feeling fancy.