Last month a client asked me to prepare a chilled soup for the first course of their dinner menu. Since June is still a bit early for tomatoes, Gazpacho—the king of chilled soups as far as I'm concerned—was not really an option. After considering the vegetable palette of early summer I decided to offer a choice between a chilled pea soup with mint (inspired by my memory of a delicious soup I enjoyed years ago in the South of France) and a chilled sweet corn and leek soup (thinking that the corn would make an interesting stand in for the potatoes in that other classic chilled soup, Vichyssoise). Either one would have been delicious, but my clients selected the Sweet Corn Vichyssoise.
I was super pleased with the way my soup turned out. Chilled soups can be refreshing and flavorful, but they can also be a bit boring and one dimensional. I'm not sure why this is so—probably something to do with the ability of our palates to discern flavor at cold temperatures—but in any case I think a chilled corn soup is particularly prone to this. The super sweet style of corn that is most often available nowadays could make for a chilled soup that is monotonously sweet. Since dessert for the first course wasn't my goal, I took several steps to insure that my soup was nicely balanced between the savory and the sweet.
Using leeks instead of onions went a long way towards rounding out the flavor of the soup. Onions would have accentuated the sweetness of the corn. Leeks, on the other hand, always add depth of flavor and in this case their subtle tang provided a nice contrast to the sweetness of the corn.
In her book Fresh From the Farmers' Market, Janet Fletcher suggests that roasting will draw out the inherent nuttiness of the corn. Since roasting is one of my favorite ways to prepare corn, I followed her advice and roasted it for my soup. To get as much flavor as possible out of the corn, after cutting off the kernels I added the cobs to the broth. This is a great idea for any corn soup since corn cobs make a delicious broth. Before discarding the cobs I took the extra step of "squeegee-ing" them by scraping them with a spoon (a stiff spatula will work too) to make sure all of the flavorful liquid went into my soup and not the compost pile or trash.
Even as I was finishing the soup, my goal continued to be providing counterpoint to the sweetness of the corn. Instead of adding heavy cream (as is my habit with puréed soups), I reached for the sour cream. It was a nice touch. I imagine that crème fraiche or a thick, creamy yogurt would be good too. I garnished each bowl of soup with a simple tomato, scallion and roasted corn relish. This brightened all of the flavors and at the same time added textural interest and much needed color.
I should point out that my recipe will produce a soup that is a bit on the thin side...perhaps on a par with the thickness of heavy cream. This was my goal. I wanted the soup to be thin enough to sip from a cup or a glass. And because I wanted it to be silky smooth, I passed it through a fine mesh strainer (pressing hard on the solids to extract as much liquid as possible). Skipping the straining step will result in a soup with the texture of thin gruel...which is not particularly appetizing.
I liked the soup so much that when I discovered this past week that I had over-purchased a bit on the sweet corn at the farmers market, I decided to make a batch of this soup for myself. It made a wonderful dinner alongside a cheese quesadilla. The next day I had a small portion for lunch with a sandwich (roast pork with yellow tomato, basil and a little goat gouda). I think it is exactly what a chilled soup should be...light, flavorful and—above all—refreshing.
Sweet Corn Vichyssoise
5 to 6 ears sweet corn (to get a generous 6 cups kernels...see note)
2 to 3 leeks, white and pale green parts only, trimmed, halved, thinly sliced crosswise (you should have 2 1/2 to 3 cups) and rinsed in several changes of water
3 cl. garlic, chopped
2 to 3 T. olive oil
3 c. water
2 c. chicken stock or low-salt canned broth (or use 2 more cups water...see note)
6 T. sour cream
Place the corn (still in the husk) directly on the rack of a preheated 375° to 400° oven. Roast for 20 to 25 minutes. Remove from the oven. When cool enough to handle, remove the husk and silks. Cut the kernels off of the cob and scrape the cobs with a spoon or the back of a knife to get all the bits of corn that remain after cutting off the kernels.
Set aside (reserving 1/2 cup separately for the roasted corn relish). Cut the cobs in half crosswise and reserve.
While the corn roasts, warm some olive oil in a large saucepan. Add the leeks and garlic, along with a pinch of salt. Gently sweat over medium low heat until the leeks have wilted and are mostly tender.
Add the corn cobs, the water and the stock.
Bring to a simmer and cook gently until the leeks are tender and the cobs have given flavor to the broth—about 30 minutes. Lift the cobs out of the stock, running a spoon (or a spatula...or the back of a knife) down all sides of the length of each cob to squeegee out as much liquid as you can. Discard the cobs. Add the reserved corn kernels to the broth and purée in batches in the blender until smooth. Don't add any more liquid unless the blender is unable to run freely. Pass the soup through a fine meshed strainer (a chinois, if you have one), pressing firmly on the solids with a ladle in order to extract as much of the liquid as possible.
Place the sour cream in a small bowl and add a small ladleful of the soup.
Whisk until smooth. Scrape this mixture back into the soup and whisk in (see note). Taste and correct the seasoning with salt and pepper. Chill deeply. Serve in chilled bowls with a spoonful of roasted corn relish in the center and drizzled with a little olive oil. Makes 6 to 7 cups of soup...serving 6 to 8 as a first course or accompaniment to a sandwich and 4 as an entrée.
- The number of ears of corn you will need will depend on where you live and where your corn comes from. I live in corn country and the ears that come to my farmers' market yield a minimum of a cup of corn per ear. To make this quantity of soup, you will need a generous 6 cups of corn kernels
- The soup will have a more well-rounded flavor if you use part stock, but if you use some stock, you must eat the soup within a day or two of making it since it will not be reheated before serving. I have made it both ways, and it is delicious either way...but I prefer all water.
- Letting out the sour cream with a small amount of the soup before adding it to the whole batch will insure that it incorporates smoothly into the soup (without lumps).
Roasted Corn Relish:
6 oz. vine ripened tomatoes (2 small or one medium)
1/2 cup reserved roasted corn kernels
1 or 2 scallions, trimmed and rinsed
sherry or red wine vinegar
salt & pepper
Core the tomatoes. Top and tail the tomatoes and cut away the outer walls as if you were cutting the peel away from a citrus fruit. Discard the inner flesh and seeds (or reserve for sauce, stock, etc.) and cut the pieces of the outer walls (called filets) into a dice the same size as the corn kernels. You will have about a half cup.
Place the diced tomatoes in a bowl along with the reserved corn. Mince the scallions using the white and an equal quantity of the green. Add to the bowl with just enough olive oil to moisten (about 2 t.) and with vinegar and salt and pepper to taste. The amount of vinegar that you need will depend on the acidity of your tomatoes. Begin with about a half teaspoon and add more to taste.
Makes about a cup of relish.