my sister made this for us once with bacon and avocado grilled cheese. delish! i of course had to make it for myself. leeks belong to the allium vegetable family with onion and garlic. i would consider them a milder and sweeter version of onions. unfortunately they aren't always easy to find. sendiks, however, hasn't let me down. it's really important to use white pepper vs. black. you'll definitely taste a difference.
potato and leek soup
1 lb leek (dark green sections removed), chopped
3 tbs butter
3 small potatoes, diced small
1 qt vegetable broth
1 c heavy cream
1 c milk
1/2 tsp white pepper
1 tsp salt plus a pinch
1 tbs snipped chives
1. melt butter over medium heat. add leeks and a pinch of salt. sweat for 5 min. decrease heat to medium low and cook until tender (25 min).
2. add potatoes and broth, bring to a boil. reduce heat to low, cover and simmer until potatoes are soft (20 min or so).
3. puree in blender or food processor until smooth (do in batches or you'll be covered in it).
4. stir in cream, milk, salt and pepper.