Potage Compiègne

Ingredients

Equipment Needed

• •4-quart heavy saucepan
• •Small skillet
• •Countertop or immersion blender
• •Fine-mesh sieve
• •Ladle and whisk

Instructions

1. 1

   Prepare the herbs

   Wash and dry the sorrel and chervil carefully. Make the cisel, the fine crosswise cut described by the classical vocabulary: stack the sorrel leaves, roll them loosely, and slice them into narrow ribbons without crushing them. Pick the chervil into pluches, the tender leaves and delicate shreds used to finish soups, discarding the coarse stems. Keep both herbs cool until needed.

2. 2

   Build the Soissonnaise

   Melt 2 tablespoons of the butter in a 4-quart saucepan over medium-low heat. Add the onion and a pinch of the measured salt, then sweat it for 8 to 10 minutes until tender and translucent without letting it color. Add the rinsed beans, bouquet garni, and 6 cups of the stock. Bring the pot to a bare simmer and cook for 20 minutes, stirring occasionally, until the onion has disappeared into the broth and the beans taste thoroughly seasoned.

3. 3

   Pass the purée

   Remove and discard the bouquet garni. Let the soup settle for 5 minutes, then blend until completely smooth, working in batches if using a countertop blender. Never fill a blender more than halfway with hot soup, and keep the lid vented beneath a folded towel. Push the purée through a fine-mesh sieve into a clean saucepan. If it still feels grainy, pass it once more rather than hiding the texture with cream; the smooth, light body is part of the dish.

4. 4

   Set the consistency

   Return the purée to medium-low heat and add enough reserved stock to make it flow from the ladle in a broad ribbon. It should leave a thin veil on the back of a spoon, never sit in a mound. If it is too thick, add stock a little at a time. If it is too thin, simmer it gently before the finishing butter goes in. Ça se rattrape. Season lightly with salt and white pepper, remembering that the final butter will round the flavors.

5. 5

   Butter the sorrel

   Melt 2 tablespoons of the butter in a small skillet over medium-low heat. Add the three tablespoons of cisel-cut sorrel with a small pinch of salt and turn it through the butter for 1 to 2 minutes, just until the ribbons collapse and become tender olive green. Do not brown them. If the butter begins to color, pull the skillet from the heat and stir in a teaspoon of cold stock; ça se rattrape, and the sorrel's clean acidity remains intact.

6. 6

   Monter au beurre

   Bring the purée just to the edge of a simmer, then remove it from the heat. Monter au beurre, mounting with butter, by whisking in the remaining 4 tablespoons of cold butter a few cubes at a time until each addition disappears and the soup becomes glossy. If butter floats in greasy beads, stop adding it and blend in a tablespoon of cold stock with an immersion blender until the emulsion returns. Once mounted, keep the pot warm but never let it boil.

7. 7

   Finish Compiègne

   Fold the buttered sorrel and every drop of its butter into the Potage Compiègne, leaving the green ribbons visible rather than blending them away. Taste once more for salt and white pepper, then ladle the soup into warmed bowls and scatter the chervil pluches over each serving at the last moment. Their freshness is brief and that is precisely their charm. À table!

Chef Tips

• •Large Soissons beans are the ideal foundation when you can find them. For one evening, canned large white beans are the honest home equivalent; butter beans or cannellini hold the smooth texture well. Rinse them thoroughly so their packing liquid does not cloud the flavor.
• •Use pale, unsalted chicken stock. A heavily roasted stock turns the ivory purée brown and overwhelms the sorrel, while a salty commercial broth leaves no room to season at the end.
• •Sorrel is not an ornamental herb here. Its clean, lemony sharpness is the counterweight to beans and butter. Out of season, frozen sorrel is the classical pantry answer; thaw it, press away excess water, and use the same weight.
• •Chervil must go on at the final moment. Its leaves bruise easily and its fragrance disappears under prolonged heat, so pick the pluches gently and keep them cool until the bowls are filled.
• •Never reboil the soup after monter au beurre. Gentle heat preserves the emulsion and its satin sheen; if the pot gets too hot, pull it aside and whisk in a spoonful of cold stock.

Advance Preparation

• •The bean purée can be cooked, blended, and passed up to two days ahead. Cool and refrigerate it before adding the finishing butter, sorrel, or chervil, then reheat gently and complete those elements just before serving.
• •For longer storage, freeze the unbuttered and ungarnished purée for up to two months. Thaw it completely, restore its flowing consistency with stock, then monter au beurre and prepare the herbs fresh.

Frequently Asked Questions

Nutrition Information

1 serving (about 245g)