Potage aux Herbes

Ingredients

Equipment Needed

• •4-quart heavy saucepan with lid
• •Large heatproof bowl and colander
• •8-inch fine-mesh sieve or tammy
• •Potato masher
• •Flexible spatula or sturdy ladle

Instructions

1. 1

   Cut and sort herbs

   Wash the herbs in cold water, lift them clear of any grit, and dry them well. Cut the sorrel julienne-fashion into fine match-shaped ribbons. Pick the chervil into pluches, the tender leaf shreds used for soups, reserving two generous pinches for the bowl. Keep the basil aside for the finish.

   Pimprenelle here means edible salad burnet, not scarlet pimpernel. Buy it under the name salad burnet and never identify a foraged plant by the common name alone.
2. 2

   Stew herbs gently

   Melt the unsalted butter in the saucepan over medium-low heat. Add the sorrel, watercress, remaining chervil pluches, pimprenelle, and a pinch of the measured salt. Stew them gently for 6 to 8 minutes, turning often, until thoroughly collapsed but never browned. Sorrel naturally turns olive as it cooks, so judge by smell and the pan floor, not by emerald colour. If the butter begins to smell nutty or the pan goes dry, pull it from the heat and add 1 tablespoon of the measured water. Ça se rattrape.

3. 3

   Simmer with potatoes

   Add the remaining water, the potatoes, and the rest of the salt. Bring the liquid to a gentle simmer, partially cover, and cook for 22 to 28 minutes. The potatoes are ready when a quarter collapses under light pressure from a spoon. Keep the simmer quiet; hard boiling bruises the herb perfume and breaks the potatoes apart before you can drain them.

4. 4

   Reserve the liquor

   Set a colander over a large heatproof bowl and drain the pot, preserving every drop of the cooking-liquor. Crush the hot potatoes and herbs together with a masher, then stir in the reserved liquor a ladleful at a time until you have a loose purée. Do not use a blender on the potatoes; its blades can turn their starch elastic and gluey. If a few lumps remain, the tammy will take care of them.

5. 5

   Pass the purée

   Set the tammy, here a sturdy fine-mesh sieve, over the cleaned saucepan. Rub the diluted purée through in batches with a flexible spatula or the back of a ladle, pressing until only dry herb fibres remain. Stir in the rest of the cooking-liquor. This passage is not brigade scaffolding to discard; it is the technique that turns potatoes and leaves into a proper potage.

6. 6

   Finish with butter

   Bring the strained soup just to one full boil, stirring across the bottom, then immediately remove it from the heat. If it is too thin, reduce it before adding the butter; if too thick, loosen it with a little hot water. Work the basil shreds into the softened Printanier butter with herbs, then monter au beurre, finish by whisking in that butter a spoonful at a time. Do not boil the soup again. If yellow droplets appear, the pot was too hot; whisk in 1 tablespoon cold water off the heat until the surface becomes smooth again. Ça se rattrape.

7. 7

   Garnish and serve

   Taste for salt and ladle the potage into warm bowls or bring it to the table in a soupière. Scatter the reserved chervil pluches over the surface and serve at once, while the basil and butter remain fragrant. À table!

Chef Tips

• •Fresh sorrel gives the potage its clean acidity. If the market's leaves are tired, use frozen sorrel picked in good condition; it is a more honest choice than spinach sharpened with lemon, which makes a different soup.
• •Pimprenelle is salad burnet, a tender garden herb with a faint cucumber flavour. It is uncommon but worth seeking from an herb grower. Never gather a wild plant sold to you only by the ambiguous name pimpernel.
• •Use water, exactly as the source directs. Stock would make a deeper soup but a less faithful one, pushing the watercress and chervil behind poultry or vegetables.
• •Printanier butter with herbs is a finished component in this formula, so have it ready before the soup begins. Plain butter will enrich the pot, but it will not carry the same herb finish; that substitution changes the dish and should be named honestly.
• •A dry Touraine Sauvignon Blanc has enough green acidity for the sorrel without overwhelming the chervil. Serve good bread beside the bowl and stop there. Cooking well is not cooking fancy.

Advance Preparation

• •Prepare the Printanier butter with herbs according to its own formula up to three days ahead and keep it covered in the cold. Soften it before the final whisking.
• •The herbs may be washed and picked earlier the same day, then wrapped in a barely damp towel and chilled. Cut the sorrel shortly before cooking so its edges remain fresh.
• •The soup can be completed through the sieving step one day ahead. Chill it promptly, reheat it to the prescribed brief boil, and whisk in the Printanier butter with herbs and basil only when serving.
• •Once finished with butter, refrigerate leftovers for up to two days and reheat over gentle heat without boiling. If the surface separates, whisk in a spoonful of cold water off the heat.

Frequently Asked Questions

Nutrition Information

1 serving (about 245g)