Ingredients

3 1/2 pounds fish bones (from whitefish, pike, or carp, or a combination), rinsed well

3 medium yellow onions, peeled and quartered

3 medium carrots, peeled and cut into 1-inch pieces

2 celery stalks, cut into 1-inch pieces

8 sprigs fresh thyme

6 sprigs fresh flat-leaf parsley

1 bay leaf

1 bottle (750 mL) dry white wine

1 medium yellow onion, coarsely chopped

1 1/4 pounds skinned pike fillets, cut into 3-inch pieces

1 1/4 pounds skinned whitefish fillets, cut into 3-inch pieces

1/2 pound skinned carp fillets, cut into 3-inch pieces

2 large eggs, plus 2 large egg whites

3 tablespoons matzo meal

1 tablespoon coarse salt, plus 3/4 teaspoon

1 1/2 teaspoons sugar

3/4 teaspoon fresh lemon juice

1/2 teaspoon freshly ground white pepper

1/4 to 1/2 teaspoon freshly grated nutmeg

1/2 cup ice water

3 medium red beets, stems and greens removed

2 tablespoons extra-virgin olive oil

Coarse salt

2 tablespoons white-wine vinegar

1 cup finely grated peeled fresh horseradish

1/2 cup white-wine vinegar

1/2 teaspoon sugar

Pinch of coarse salt

2 bunches fresh dill, separated into small sprigs

2 bunches fresh flat-leaf parsley, separated into small sprigs

1 bunch fresh chives (about 12), cut into 1-inch pieces

Preparation

Make the stock: Put fish bones, onions, carrots, celery, herbs, wine, and 10 cups cold water into a large stockpot. Bring to a boil; reduce heat, and simmer, skimming foam from surface, 40 minutes. Pour through a sieve into a bowl; discard solids. Let cool completely. Cover, and refrigerate until cold (up to 2 days).

Make the quenelles: Finely chop onion in a food processor. Add half the pike, whitefish, and carp; process until smooth, scraping down sides of bowl halfway through. Transfer to a large bowl. Puree remaining fish. Return first batch of fish to the processor, and pulse to combine.

With machine running, add eggs and egg whites; process until just combined. Transfer to bowl. Stir in matzo meal, salt, sugar, lemon juice, pepper, and nutmeg. Add ice water in a slow, steady stream, stirring until combined. Press through a large-mesh sieve into another bowl. Refrigerate 30 minutes (up to 1 day).

Bring stock to a gentle simmer in a large saucepan. Shape quenelles using two wet soup spoons: Use one spoon to scoop up a mounded spoonful of batter; slide second spoon on top of first, with spoons pointing in opposite directions. Spoon the batter back and forth a few times, scraping it into a small, neat egg shape. Drop quenelles into simmering stock as you form them, working in batches of 8. Cook until quenelles float and surface springs back when lightly pressed, about 8 minutes. Using a slotted spoon, transfer quenelles to a large, shallow bowl as they are done. Strain stock over quenelles in bowl; cover, and refrigerate overnight.

Prepare the beets: Preheat oven to 350. Toss beets with oil and 3/4 teaspoon salt in a medium bowl. Arrange beets on a rimmed baking sheet; cover with foil. Bake until beets are very tender when pierced with the tip of a knife, 45 to 50 minutes. Let cool 10 minutes; peel. Cut into 1/4-inch dice, and transfer to a medium bowl. Add vinegar, and toss; season with salt. Cover, and refrigerate until ready to use (up to 2 days).

Make the horseradish: Stir together horseradish, vinegar, sugar, and salt in a bowl. Cover, and refrigerate up to 1 day.

Remove quenelles from refrigerator 30 minutes before serving. To serve, spoon 3 quenelles and about 2 tablespoons stock into each bowl. Place 1 tablespoon beets and 1 tablespoon horseradish next to quenelles, and garnish with herbs. Place remaining horseradish in a small bowl, and serve on the side.