Foraging II: Mushroom soup extraordinaire

The mushroom soup I mentioned at the end of my last post was amazing.

After hunting around a bit online, I decided to use Hank Shaw's adaptation of a recipe by famed French chef Auguste Escoffie, Velouté Agnes Sorel. Actually, I adapted Shaw's adaptation, but even this third-generation version was wonderful: rich, thick, and tasty. On his blog Hunter Angler Gardener Cook, Shaw details how his version differs from Escoffier's, and I thought I'd continue that tradition by explaining how mine differs from Escoffier's.

The basic formula for the soup is simple and basic: make a sauce with roux and chicken stock, add sautéd onions and mushrooms, and purée. Yet Shaw warns that this soup is not a quickie. He's right, but if you skip mincing the mushrooms (why bother, as they'll be blenderized into mini-fragments anyway?), it's not really labor-intensive; it just requires attention and time for things to simmer. It also includes a few special touches: saffron, liqueur, and cream.

Shaw added the saffron and brandy to the recipe, and specifies chanterelles. Not having brandy, I used cooking sherry (about ¼ c.); ditto for using yellow onion instead of shallots. I skipped the final butter addition; my chicken stock, made a few days earlier, hadn't had the fat skimmed off, so I figured I had extra fat in there already.

According to Shaw, this soup “screams for Chardonnay—or at least some sort of full-bodied white that's gone through malolactic fermentation.” Malolactic isn't the only word I encountered for the first time in this recipe: velouté (for which Shaw kindly provides the pronounciation (vel-oo-TAY) and liason were both new to me.

(I had to look up malolactic fermentation, a wine-making term that refers to the conversion of sharp-tasting malic acid into smoother, fuller-bodied lactic acid. My my.)

A velouté turns out to be something I've often made, but didn't know the word for: a white sauce, made by stirring a light stock into a roux of butter and flour. A liaison is a binding or thickening agent, typically a mixture of cream and egg yolks used to thicken soups or stews. To keep the egg yolks from cooking and curdling, small quantities of the hot soup are added to the liaison and stirred in completely, gradually raising its temperature until it can be safely added to the main pot.

I skipped the egg yolks as well, going with plain old cream. Shocking, I know, but as I say, the results were still wonderful.

Escoffier's name for the soup, Velouté Agnes Sorel, apparently refers to the basic sauce, velouté, while Agnes Sorel was a (get that–a, as in, one of several) favorite mistress of King Charles VII of France. According to the online Babylon dictionary, it is also "A garnish made of mushrooms, chicken, and pickled tongue named after the mistress of King Charles VII of France. In Agnes Sorel soup, the garnish is cut into thin strips and added to the thickened soup." Precisely how Agnes' name became attached to a garnish featuring pickled tongue (maybe she was fond of the stuff?), much less how it got attached to a soup that doesn't feature it, I don't know.

Here's the recipe, which serves four to six.

VELOUTÉ

Warm 6 cups chicken stock.

Melt 2 tablespoons unsalted butter over medium heat.

Stir in 2 tablespoons flour.

Add the stock bit by bit, whisking until smooth after each addition. Cook over low heat, stirring frequently to prevent lumping or sticking, for 20 minutes.

SOUP

Clean 4-5 c. (10-16 oz.) chanterelles. I've found it simplest to dump them into a bowl of water, stir them around, and then drain.

Put the chanterelles into a large frying pan on medium heat to sweat. Unless they're very dry, they will give up enough water to float. Every source I've seen says to boil this off, but I pour it off and save it.

Chop 4-8 T onion, or 2 shallots.

When the chanterelles are dry, add 2 T. butter and the onions. Sauté until onions are translucent.

Crumble a pinch of saffron into ¼ c. cooking sherry and stir it into the mushrooms. Continue to cook until most of the liquid has boiled off.

Either purée the mushroom/onion mixture, or add it to the velouté and then purée. Simmer slowly for ten minutes.

For a garnish, chop a few remaining mushrooms and sear them in a dry pan or with a bit of butter; set aside.

Remove the soup from the heat and add ½ c. cream to it. Serve. the souinto a small bowl, and whisk in a couple of tablespoons of the soup. Repeat, stirring thoroughly each time, until you have raised the temperature of the cream.

(Shaw and, I presume, Escoffier, have you whisk three egg-yolks into the cream. If you do this, you must temper this liaison before adding it to the hot soup, or the eggs will cook instantly, congealing into lumps. To avoid this, whisk hot soup into the liason bit by bit to raise its temperature gradually before pouring it into the pot.)

Salt to taste.

Pour into bowls, add mushroom garnish, serve, and enjoy.