Spring cauliflower soup

My favorite Paris bistro at the moment has an American chef.
To me there is nothing really surprising about this. After all, I'm Canadian and teach Niçois cooking, much to the initial alarm of the market vendors at the Cours Saleya (who have now accepted and even occasionally embraced me).
Former philosophy student Daniel Rose has solid credentials, having worked with the likes of Yannick Alléno, the brilliant young chef at Le Meurice. He also has a passion for the freshest ingredients, which is why he cooks up a single four-course menu every day with no substitutions at his bistro Spring. The only concession he makes in this age of food allergies, intolerences and general fussiness is to ask customers on the phone if there is anything they don't eat. He then tries to adapt the menu to the tastes of those who fill this little dining room in the 9th arrondissement every night.
On the day I ate at Spring, Rose had come back from the Place des Fêtes market in the 19th arrondissment with a giant octopus and transformed it into a meaty salad with new potatoes, crunchy radishes and herbs. He served generous chunks of poached guinea hen with roasted beet, carrot and parsnip, giving one customer who was unfamiliar with this vegetable a giant parsnip to take home. In his open kitchen he grated lime zest over a dozen plates of baked apple with pain perdu (French toast), walnuts and cream, bringing this homely dessert to life.
The dish that really stuck with me, though, was the crème de chou-fleur sans crème that started the meal. Cauliflower is not the sexiest vegetable, at least not normally. In Paris and Nice, though, you can sometimes find sweet young cauliflowers still encased in their pale green leaves, which don't have the strong cabbagey flavor of bigger cauliflowers. These are perfect for this velvety soup, which smacked of luxury despite the lack of cream. I had to know what Daniel's secret was, so e-mailed him the next day asking for the recipe. Below is his reply, which I haven't bothered to edit (except for adding US measurements) as he has written the recipe so nicely.
I've published a full review of my meal at Spring in the June issue of Paris Notes, for which I write a monthly restaurant column. I tried the soup as soon as Daniel sent me the recipe and I'm happy to report that he omitted nothing - it was wonderful. The version he served was with browned butter, toasted almonds and currants, but I plan to try the other variations too.
Sorry about the shadow in the photo but when I took this picture I was trying not to make it obvious that I was a restaurant critic (Daniel looked at me suspiciously anyway).


The cauliflower soup is very simple...

2 heads of cauliflower
1.5 medium sized yellow onions
salt and pepper
butter (demi-sel)
olive oil
sweat the sliced onions in the olive oil and butter
once nearly cooked, add just enough water (or chicken stock) to cover the onions, (under) season with salt and pepper and let reduce on medium heat
once nearly dry, add the chopped cauliflower (1/4 inch slices, then roughly chopped) and continue cooking on medium-high heat until the cauliflower is mostly cooked through and there is a strong, sweet smell of roasted cauliflower
cover with water (or chicken stock), season with coarse salt, and cook until the cauliflower is very soft.
Blend the soup in a powerful mixer in several small batches until it is very smooth. reheat, reseason
Spring garnishes vary, these are my favorites:
-jus de pigeon
-beurre noisette (browned butter), toasted almonds, currants
-chervil, crème fraîche
-curried pintade (guinea hen)
-roasted apple and vanilla

Sorry, I couldn't tell you how much butter/oil I use... I just do it!
about 70g (2 oz) of butter and a few squirts of olive oil?

Spring, 28 rue de La Tour d'Auvergne, 9th, 01 45 96 05 72.