Delicate vichyssoise can be made with any number of vegetables; this version uses zucchini. (Meredith Deeds, Special to the Star Tribune/The Minnesota Star Tribune)

Sometimes the simplest things can be the best. Or, in the case of vichyssoise, the most delicious.

Vichyssoise (pronounced VISH-ee-SWAHZ) is an iconic French chilled soup made with butter, leeks, potatoes, cream and not much else. It's so luxurious that it's hard to believe it isn't more complicated.

It starts with sautéing leeks and onion in butter just until softened. But don't brown them; that gives the leeks a stronger flavor, and in this soup, every flavor needs to shine through and balance with the others.

Potatoes are also a key ingredient, and many aficionados have strong feelings about which variety makes the best soup. Some insist on Russets, which have a lot of starch, and others call for red potatoes, which are low-starch. My favorite for this recipe is Yukon Gold, which lies somewhere in the middle. They are rich in flavor with a fairly firm but moist texture and a medium starch content, giving the soup body without getting in the way of its silky-smooth texture.

While it takes just a handful of ingredients to make this soup special, it's also the perfect vehicle to highlight some of summer's other bounty, like zucchini.

Zucchini fits perfectly into this soup because its delicate flavor comes through without overwhelming anything else. But it's not your only option. Peas and cauliflower both make lovely additions, as does any vegetable that isn't too intensely flavored.

Vichyssoise, for all its elegance and sophistication, is incredibly easy to make, but you do need to think ahead. It takes at least four hours to chill, which makes it a great make-ahead dish. Remember to taste it right before serving, as chilling a dish can mute its flavor.

You can serve vichyssoise with a crisp green salad, but honestly I'm happy with just a little crusty bread. Vichyssoise deserves to be the star of the show.

Zucchini Vichyssoise

Serves 6 to 8.

Note: Vichyssoise, a chilled leek and potato soup, is the perfect solution to "what's for dinner" on a hot summer night, and it's even better with the addition of zucchini. You'll need to prepare this recipe in advance to give it time to chill. From Meredith Deeds.

• 3 tbsp. unsalted butter

• 3 medium leeks, cleaned and chopped

• 1 large yellow onion, chopped

• 1 lb. Yukon Gold potatoes, peeled and cut into 1 1/2-in. cubes

• 4 c. vegetable or chicken stock

• 1 1/2 c. water

• 3/4 tsp. salt

• Freshly ground black pepper

• 2 medium zucchini, trimmed and chopped

• 1 c. heavy cream

• 1 tbsp. lemon juice

• Chopped fresh chives

Directions

Heat the butter in a large pot over medium heat. Add the leeks and onion and cook, stirring frequently, until softened, about 6 minutes.

Add the potatoes, stock, water, salt and black pepper and bring to a boil. Reduce to a simmer and cook partially covered until the potatoes are just tender, about 25 to 30 minutes. Add the zucchini and cook, partially covered, until tender, about 10 to 15 minutes.

Remove from heat and stir in cream and lemon juice. Let cool for 15 minutes. Working in batches, purée, using an immersion blender, blender or food processor. (If using a blender, do not fill more than halfway, remove the plastic insert in the lid and cover with a dish towel.)

Pour the soup through a fine-mesh strainer into a large bowl and chill for at least 4 hours. Before serving, taste and re-season with salt and pepper, if necessary. Pour into bowls and garnish with chives.