Mushroom Soup

In the medium saucepan, melt 2 tablespoons/28 g of the butter over medium heat and add the onion. Cook until the onion is soft and translucent, then add the mushrooms and the remaining butter. Let the mixture sweat for about 8 minutes, taking care that the onion doesn't take on any brown color. Stir in the chicken stock and the parsley and bring to a boil. Immediately reduce the heat and simmer for about an hour.

After an hour, remove the parsley and discard. Let the soup cool for a few minutes, then transfer to the blender and carefully blend at high speed until smooth. Blend in stages with the blender's lid firmly held down.

When blended, return the mix to the pot, season with salt and pepper, and bring up to a simmer again. Add the sherry, mix well, and serve immediately.