Mushroom soup
6 tablespoons butter
1 small onion, thinly sliced
12 ounces button mushrooms
4 cups chicken stock or broth
1 sprig of flat parsley
Salt and pepper
2 ounces high-quality sherry (don't use the cheap grocery-store variety; it's salty and unappetizing and will ruin your soup)
  1. In a medium saucepan, melt 2 tablespoons of the butter over medium heat and add the onion.
  2. Cook until the onion is soft and translucent, then add the mushrooms and the remaining butter.
  3. Let the mixture sweat for about 8 minutes, taking care that the onion doesn't take on any brown color.
  4. Stir in the chicken stock and the parsley and bring to a boil.
  5. Immediately reduce the heat and simmer for about an hour.
  6. After an hour, remove the parsley and discard.
  7. Let the soup cool for a few minutes, then transfer to a blender and carefully puree at high speed until smooth.
  8. When blended, return the mix to the pot, season with salt and pepper, and bring up to a simmer again.
  9. Add the sherry, mix well, and serve immediately. Garnish with truffle oil, if you have any.