Ingredients
Method
- Melt butter in a large pot over medium-low heat. Add onions and cook 25–30 minutes, stirring, until deep brown and sweet.
- Push onions to the side, add mushrooms and garlic, and cook 6–8 minutes until mushrooms release liquid.
- Stir in flour and cook 1 minute. Gradually add broth, scraping browned bits.
- Add thyme, simmer 10 minutes. Stir in milk, heat through, and season.
- Use an immersion blender for a smooth soup or leave chunky. Serve warm.