Mushrooms have a deep, savory flavor that blends beautifully with thyme and cream in this simple cold-weather soup recipe. This recipe is adapted from the Wild Mushroom Soup recipe in my first cookbook - The Nourished Kitchen (Ten Speed Press 2014).
Warm the butter and olive oil in a large pot or large Dutch oven over medium heat. When the butter froths, toss in the shallot and celery, sautéeing them in the hot fat until they soften and become fragrant - about 6 minutes. Deglaze the pan by stirring in the white wine, scraping up any browned bits on the bottom of the pot.
Stir in the mushrooms. Sprinkle them with thyme, salt, and pepper. Stirring occasionally, let the mushrooms cook with the shallot and onions until they soften and release their liquid, about 3 minutes further.
Pour in the broth and bring to a boil over medium-high heat. When the pot reaches a boil, turn down the heat to medium-low and simmer until the mushrooms are completely soft and cooked through - about 20 minutes further.
Turn off the heat and stir in the cream. Then, blend the soup with an immersion blender until smooth. Ladle into bowls and serve right away, or transfer it to the fridge to keep up to 3 days.