Snowed in for the past 4 days, this soup was developed out of necessity. I wanted to make a leek and potato soup, but found all we had was yellow onions and a few potatoes. I had simmered up the bones of a roast chicken the other day and so had the makings of a simple, tasty and cheap soup. Caramelizing the onions is not at all difficult, but it does take time and an old-fashioned pot (read: not non-stck). Be patient, it is worth the effort.
1 tablespoon vegetable oil
3 small yellow onions (or 2 medium), peeled and sliced thin
2 tablespoons dry sherry
3 quarts good quality chicken broth (homemade is best, but whatever you’ve got hanging around)
2 large potatoes (whichever you got), peeled and cubed
1) Pour the oil into a large soup pot and set over medium-low heat. Add in the onions and stir to coat with the oil.
Cook ever so gently, stirring every few minutes…
until the onions are golden and caramelized- this will take about 20 to 30 minutes. You want a golden fond to develop on the bottom of the pan, but do not want to burn the onions- don’t be tempted to raise the heat, this is a slow process. If the pot get’s too dry and the onions stick too much, spoon in a bit of water, just don’t do this too often or the onions will braise rather than color and caramelize.
2) When the onions are ultra soft and caramel in color, add in the sherry and scrape up all the fond (golden/brown bits on the bottom of the pot). Next, add in the stock and then the potatoes. Simmer until the potatoes are very soft (about 15 minutes) then remove from heat and puree with an immersion blender or in a standard blender or food processor. Finish with cream if you like, taste for seasoning, add salt if you wish and serve hot (a scattering or Gruyere croutons would be fabulous).
Makes about 3 and 1/2 quarts. Great made a day ahead and reheated as needed.