Serves 6

2 tablespoons unsalted butter
2 yellow onions, chopped
3 leeks, white parts and 1-inch of the green, halved lengthwise, washed and sliced crosswise
1 clove garlic, minced
1 tablespoon curry powder
3 cups vegetable stock
4 red potatoes, about 1 pound, peeled and thinly sliced
to taste salt
1 teaspoon freshly ground pepper
3 cups milk, or as needed
2 tablespoons finely chopped fresh chives

Melt butter in soup pot over medium-low heat. Add the onions and leeks and sauté, stirring, until the vegetables begin to soften.
Add the garlic and curry powder and sauté until onions and leeks are soft.
Add the vegetable stock, potatoes and 1 teaspoon salt. Cover and cook until the potatoes are soft. Pour in the 3 cups milk and stir to mix well.
Working with 2 cups of soup at a time, place in a blender and purée on high until very smooth and light.
As each batch is puréed , transfer to a large bowl.
If the soup is too thick ,add more milk and stir until the soup is the consistency of heavy cream.
Cover and chill for 2 hours. Season to taste with salt and pepper. Laddle into chilled bowls and garnish with the chives.