Rehydrate the Porcini Mushrooms: Place the dried porcini mushrooms in a bowl, cover with 1 cup (250 ml) of hot water, and soak for 15-20 minutes until softened. Remove, finely chop, and reserve the soaking liquid, leaving any sediment behind.
Sauté the Onions and Garlic: In a large pot, heat the butter and olive oil over medium heat. Add the diced onions and sauté for 3-4 minutes until they become soft and translucent. Stir in the minced garlic and cook for another minute until fragrant.
Cook the Mushrooms: Add the fresh mushrooms, chopped rehydrated porcini mushrooms, and thyme to the pot. Cook for 7-8 minutes, or until the mushrooms release their liquid and become tender.
Deglaze with Wine: Pour in the white wine and cook for 2-3 minutes, stirring occasionally, until the wine reduces slightly.
Add the Flour: Sprinkle the flour over the mushroom mixture and stir well to coat evenly. Cook for 1-2 minutes.
Incorporate Broth and Porcini Liquid: Gradually pour in the chicken broth along with the reserved porcini soaking liquid, stirring continuously to avoid lumps. Bring the soup to a boil, then reduce the heat to low. Season with salt and black pepper to taste.
Simmer: Cover and simmer for 10-15 minutes, stirring occasionally, until it thickens slightly and flavours meld.
Blend and Add Cream: Use an immersion blender to puree the soup until smooth and creamy. Stir in the cream and lemon juice. Let the soup simmer for a few more minutes (do not boil) to warm through. Taste and adjust seasoning as needed.
Serve: Ladle the soup into bowls, garnish with fried mushrooms (optional) and chopped parsley, and serve warm. Enjoy!
Store and Reheat: Store the cream of mushroom soup in an airtight container in the refrigerator for up to 4 days. Reheat gently on the stove over medium-low heat, stirring occasionally. Avoid boiling to maintain its creamy texture (otherwise the cream may curdle).
Freeze Without Cream: Freeze the soup base without cream. When reheating, stir in the cream to prevent curdling or texture changes.
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