Potato-leek soup has been with me for a long time. Most famously it was the base for an asparagus-potato-leek soup I made for President Jimmy Carter years ago, when I worked as a bookseller and he came to our store to sign a book of poetry. Back then I followed a recipe from Perla Meyer's Art of Seasonal Cooking, but nowadays I let my pantry (by which I mean, all my food storage areas: my pantry, freezer, fridge, and even my garden--I'm "storing" potatoes there now) guide me instead. I discovered a quart of spring 2009 asparagus lingering in the freezer this weekend and with the hints of spring 2010 popping up all over the place (why, Hello, Hyacinths!), I thought that would be a good addition. Annabel wanted a cheese soup, so grated cheddar went in too. (She even agreed that potatoes, as long as they were pureed, would be okay, which is a big step for a girl who has hardly let potato in any form pass her lips in three years.)
The twist? We're out of chicken broth. And vegetable stock. There's a jar or two of beef broth in the pantry, but I've always thought that beef is too rich for this soup, which has a light spring air about it, especially with the asparagus. I have been saving up chicken backs and veggie scraps in the freezer for my upcoming Stocks, Soups, and Stews class and not made any stocks for my own use lately. What to do? A friend recently asked on Facebook what she could do with the abundant whey she had leftover from making cheese. Someone suggested soup and, fortunately, I have lots of whey too. So, into the pot that went as well. I was concerned that it would add an excessively tangy flavor, but not at all. If you have "way too much whey" on hand, here's a way to use some up...otherwise, chicken broth or vegetable stock will be just fine.
2 tablespoons butter
2 large leeks, white and pale green parts sliced
2 pounds potatoes (I used German butterballs from our garden), chopped
2 cloves garlic, minced
2-3 cups whey (or chicken broth or vegetable stock)
1 pound frozen asparagus
1 generous cup grated cheddar cheese
creme fraiche, sour cream (optional)
bacon bits (optional)
Melt butter in a soup pot over medium high heat. Sauté the sliced leeks in butter until soft. Add the potatoes and garlic, then add enough whey to cover everything. Bring to a boil, then reduce heat and simmer for 20 minutes or until potatoes are soft enough to mash with a fork. Add the asparagus and cook for a couple minutes, long enough to barely soften the asparagus. Remove pot from heat and purée with an immersion blender or in batches in a blender or food processor. Return the puréed soup to the pot and add the cheese. When the cheese is melted, add salt and pepper to taste. Serve with a dollop of cream fraiche or sour cream and a sprinkling of bacon bits.