Potage Rossolnik

Ingredients

Equipment Needed

• •4-quart heavy saucepan
• •Food processor with metal blade
• •Fine-mesh sieve
• •Two teaspoons for shaping quenelles
• •Slotted spoon
• •Instant-read thermometer

Instructions

1. 1

   Make cold forcemeat

   Chill the food-processor bowl and blade for 10 minutes. Process the very cold chicken with the salt and 1/8 teaspoon white pepper until the meat becomes smooth and tacky. Add the egg white and process again, then pour in 1/2 cup of the cold cream in four small additions, stopping to scrape the bowl and check its temperature. The forcemeat must remain cold enough to feel firm, never warm or greasy. Scrape it into a bowl, cover, and chill for 20 minutes. If it turns grainy or begins shedding fat, stop immediately, chill it for 15 minutes, then process briefly with one spoonful of cold cream. Ça se rattrape.

   Poach one teaspoon of forcemeat as a test. It should hold a smooth oval and feel tender, not rubbery. If it spreads, chill the mixture longer before shaping the rest.
2. 2

   Poach small quenelles

   Heat 2 quarts of the water to 175 to 180°F (79 to 82°C), a bare tremble with no rolling bubbles. Dip two teaspoons in the water, scoop up the forcemeat, and pass it between the spoons to form 24 small ovals. Poach them in batches for 6 to 8 minutes, turning once, until firm and 165°F (74°C) at the centre. A hard boil roughens the surface and tightens the chicken, so lower the heat if the water becomes lively. Lift the quenelles out with a slotted spoon, cover, and keep chilled if the soup will not be finished within 30 minutes.

3. 3

   Cut the garnishes

   Cut the parsley root into 20 tapered pieces and the celery root into another 20, each about 1 1/4 inches (3 cm) long and 3/8 inch (1 cm) thick. Make a shallow cross-cut in the thicker base of every piece, preserving the source's little new-carrot shape without wasting half the root through formal turning. Slice the salted cucumbers diagonally into 40 small lozenges. Bring the remaining 2 quarts water to a gentle boil, add all the roots and cucumber lozenges, and parboil them together for 15 minutes. Drain thoroughly.

4. 4

   Build pale velouté

   Melt the butter in a heavy 4-quart saucepan over medium-low heat. Add the flour and stir for 3 minutes to make a roux blanc (white roux), cooking away the raw flour taste without allowing it to colour. Gradually whisk in 7 1/4 cups of the cool chicken stock, beginning with small additions so the roux opens smoothly. Bring it slowly to a bare simmer and skim off the pale foam. If lumps remain, blend the velouté briefly and pass it through a fine sieve now, before the garnish enters. Nothing is lost.

   Cool stock meeting warm roux gives you time to whisk the mixture smooth. Hot stock poured in all at once traps flour inside stubborn little knots.
5. 5

   Simmer and skim

   Stir 3/4 cup of the cucumber juice into the velouté, then add the drained parsley root, celery root, and cucumber lozenges. Hold the pot at the gentlest simmer for 40 minutes, skimming the surface whenever foam gathers. The velouté should lightly coat a spoon while the root pieces become completely tender. If it tightens too far, loosen it with the reserved 1/4 cup stock; if it remains thin, let it simmer uncovered a few minutes longer. Add the poached quenelles for the final 5 minutes so they warm through without toughening.

6. 6

   Finish with liaison

   Whisk the egg yolks with the remaining 1 cup cream to make the liaison ordinaire (ordinary egg-yolk-and-cream enrichment). When the 40-minute simmer is complete, reduce the heat to its lowest setting and stir the reserved 3 tablespoons cucumber juice into the pot. Whisk two ladles of hot velouté gradually into the liaison, remove the saucepan from the heat, and stir the tempered liaison back into the soup. Return it to the lowest heat only long enough to reach 170 to 175°F (77 to 79°C). Never let it boil. If grainy yolk flecks appear, pull the pot off the heat, lift out the solid garnishes, blend the liquid briefly, and pass it through a fine sieve into a clean saucepan before returning the garnish. Ça se rattrape.

   Taste before reaching for salt. The stock was left unsalted because the cucumber juice must supply the soup's clean saline edge.
7. 7

   Serve the potage

   Stir in the remaining 1/4 teaspoon white pepper and taste for balance. The first impression should be light poultry and cream, followed immediately by a bright, clean cucumber tang. Ladle the potage into warmed soup plates, giving each serving three or four quenelles and a fair share of the roots and cucumber lozenges. Serve at once. À table!

Chef Tips

• •The source fixes the finishing cucumber juice at one and one-half tablespoons per quart but leaves the amount incorporated into the initial velouté unstated. Three-quarters cup at this doubled scale suits a clean, moderately salty brine, while the final three tablespoons preserve the stated finish exactly.
• •Buy naturally fermented salted cucumbers from the refrigerated case, with their brine. Vinegar pickles and cornichons give a sharp, one-note acidity rather than the rounded lactic tang Rossolnik needs.
• •Parsley root is not parsnip. It has an herbal, celery-like character and far less sweetness, which matters against the cream. Ask for Hamburg parsley root if the market uses that name.
• •Use pale, unsalted chicken stock. A roasted brown stock muddies the ivory colour and overwhelms the cucumber, while a salted carton leaves no room to control the brine.
• •For wine, pour a taut, very dry white with little oak. The soup already has cream and acid; it wants freshness beside it, not more weight.

Advance Preparation

• •The velouté, roots, and cucumber lozenges can be cooked through their 40-minute simmer one day ahead. Chill promptly, then reheat gently before adding the quenelles, final cucumber juice, and liaison.
• •The chicken quenelles can be poached one day ahead and refrigerated in a covered container. Warm them in the potage during its final 5 minutes of simmering.
• •Once the liaison has been added, reheat leftovers over low heat while stirring and never allow them to boil. Freezing is unkind to both the liaison and the quenelles.

Frequently Asked Questions

Nutrition Information

1 serving (about 250g)