Serve this puree with our Oven-Baked Potato Pancakes.
Cut leeks in half lengthwise, then into 1/4-inch-thick slices. Place in small bowl, and cover with cold water. Let stand for 5 minutes to rid leeks of dirt and sand. Lift out of the water, and drain.
Heat oil in saucepan over medium heat. Add leeks, peppers, salt, and pepper; saute for 3 minutes. Add stock; cover. Cook until vegetables are tender, about 12 minutes.
Transfer vegetables to food processor; puree. Pass puree through fine strainer back to saucepan. To serve, warm over low heat.
An orange or yellow bell pepper can be used in place of the red.