Enjoy it piping hot, and you'll see that the tender flavor of cauliflower and the tangy taste of sorrel go very well together.
Remarks
Kervallon is an area of the city of Brest (France), which in the late 18th century was a market garden where many vegetables were grown. Today, it's a very pleasant area, partly wooded, and home to numerous allotments.
If in step 8 you still can't obtain a homogeneous mixture after blending, add 2 tablespoons of cornflour diluted in a little cold water and thicken by whisking over the heat.