2 tablespoon canola oil
10 russet potatoes, peeled and cut into large pieces
6 leeks (whites only), thoroughly washed and sliced
1 tablespoon flour
6 cups vegetable stock, approximately. (I use Trade Joe’s soup stock in the box.)
Salt and freshly ground pepper
In an 8-quart stock pot, sauté leeks until soft. (Don’t allow them to burn.) Add flour and mix continuously for 2 minutes on low flame. (This will help thicken the soup.)
Put potatoes and stock into the pot. Sprinkle with salt and pepper. Boil until the potatoes are soft, 15 to 20 minutes.
When potatoes are soft, use an immersion blender until the soup is smooth and simmer until the soup has thickened, about 20 minutes.
Note: To avoid a too-watery soup, add only enough stock to cover potatoes.