Potato leek soup is really one of the most delicious yet simple things on earth. But we can’t always find leeks year round, and they’re typically pretty expensive. AND, they can be downright impossible to clean, with all the grit that accumulates between their layers. (And when you wash out that grit, you wash away a considerable amount of flavor.) Luckily, onions make a very acceptable substitute, which means this is an inexpensive soup with simple, long-storage ingredients that you can make any time of year.
Incidentally, the French classic “vichyssoise” (pronounced “VISH-eh-swah”) is nothing more than cold leftover potato leek soup. Even the French knew that day-old soup tastes better, and they charge a premium for it!
I make this soup in my pressure cooker, which makes quick work out of it. I can turn this soup out in 30 minutes. If you don’t have a pressure cooker, count on around 90 minutes’ cooking time. But it’s worth it. You can add all sorts of extra yummies to this soup…bacon is one of my favorites. Cheese is another…any grated cheese can be stirred in right at the end to enrich the soup.
2 medium yellow onions, diced (or 6 medium leeks, sliced up to the first leaves, washed)
4 Tablespoons unsalted butter (or bacon fat?!?)
2 teaspoon kosher salt (or 1 tsp table salt)
Saute the salted onions or leeks in butter over medium heat for about 10 minutes. The heavier the pot you use, the better the result. Then add:
4 medium potatoes, peeled and cut into 1/2″ cubes
6 cups chicken broth (or veggie broth if you’re cooking vegetarian)
2 Tablespoons vinegar (I use apple cider)
Bring to a boil, lower the heat, and simmer until potatoes are tender. (Or, pressure cook at 15psi for 8 minutes.) At this point, if I’m making the soup for myself, or for a nice dinner, I’ll use my immersion blender to blend it smooth. But my neighbor Sharon likes it chunky so I’ll blend it just a little until it begins to thicken, but will leave big chunks for her. Finish the soup with:
2 cups buttermilk
Stir until smooth, then taste. The soup will PROBABLY need more salt. Maybe even a considerable amount, depending on the salinity of the broth. (Sometimes I add up to a Tablespoon or more.) If it’s salty enough but you’re still missing “something,” that something is acidity, so add another glug of vinegar. At this time you can add other ingredients…sriracha (red pepper sauce) is a favorite. Chopped chives or scallions is another. Crumbled bacon. Shredded cheddar or pepper jack. Sour cream. Your imagination is the limit.