Onions: In a soup pot or a dutch oven, heat the oliveoil over medium heat. Add onions and sprinkle with salt. Stirring often, cook the onions until they begin to brown, about 8 minutes. Add garlic and thyme, continue to cook, stirring occasionally for about 2 minutes. Using a slotted spoon, remove the onions from the pot and set aside, leaving the oil in the pot.
Mushrooms: Add mushrooms to the pot the onions were cooked in. Arrange the mushrooms in a single layer at the bottom of the pot. Sprinkle with salt and cook undisturbed for about 5 minutes. Stir 1 - 2 times more and continue to cook until golden brown all over, about 5–7 minutes longer. Sprinkle flour over the mushrooms and toss to coat evenly. Cook for another 2- 3 minutes undisturbed. Add the sherry and cook for an additional 3 - 5 minutes undisturbed. The mushrooms should be very brown and possibly caramelized.
Stock: Add the stock and onions to the mushrooms. Bring to a boil. Once boiling, reduce the heat, cover, and allow to simmer for 20 minutes. Remove from heat and use the stick blender to blend soup until desired creaminess. Add the 2/3rds of the cream to the soup and stir.
Serve: Pour into bowls, top with remaining cream and desired garnishes.
Garlic Croutons (optional)
Prep: Preheat the oven to 350. Line a baking sheet with parchment paper. Cut the bread into cubes.
Make and Bake: Toss the bread cubes in oliveoil and garlicsalt. Arrange on a baking sheet. Bake for 12 - 15 minutes, until the croutons are at the desired toastiness.
Notes
For a creamier soup, add up to an additional 1/2 cup of heavy cream
For a lighter soup, you can substitute half and half for heavy cream.
Storage - Refrigerator - Transfer the soup into an air-tight container. Soup can be store this way in the refrigerator for up to three days.
Storage - Freezer - I do not recommend freezing this soup.
The equipment section may contain affiliate links to products used in this recipe.