Add flour, stock and milk. Season with salt & pepper and cook 8 minutes / 100 degrees / speed 2. MC off with the simmering basket on the lid.
Add lemon juice and cream, mix 20 seconds / speed 3. MC on.
Blend 1 minute / increasing speed up to speed 8.
Notes
If using the TM6 measuring cup (MC), when cooking at temperatures over 95 degrees, Thermomix recommends using the simmering basket on the lid in place of the MC.