1. In a saucepan, melt 1 tablespoon of butter. Add the onion, celery, and carrot. Cook for 1 minute. Add the potatoes and mix.
2. Add the chicken broth. Bring to a boil. Let simmer for 5 minutes.
3. Add the dried mushrooms, reduce heat and let simmer for 15 minutes.
4. In a pan, melt 2 tablespoons of butter. Add the Paris mushrooms. Cook for 5 minutes over medium heat.
5. Add the Paris mushrooms and their cooking juice to the saucepan. Let cook for 15 minutes over medium heat.
6. Blend all the ingredients with an immersion blender to get a smooth soup.
7. Transfer to a soup bowl and serve.