Ingredients
Method
- Melt butter in a pot over medium heat and cook onion until soft, about 5 minutes.
- Add mushrooms and cook until they release liquid, about 7 minutes.
- Stir in flour and cook 1 minute.
- Gradually add broth, stirring until smooth, then simmer 10 minutes.
- Stir in milk, Parmesan, and lemon zest. Heat gently; do not boil.
- Season to taste and serve warm.