1. Wash and quarter mushrooms. Peel and quarter the onion, garlic and leeks.
2. Place mushrooms, onions, leeks, broth, butter and flour in the bowl fitted with the ultrablade knife. Season with salt and pepper.
3. Launch the P1 soup program for 25 minutes.
4. At the end of the program, add cream and mix at speed 11 for 30 seconds.