Ingredients

2 tablespoons extra-virgin olive oil 

2 medium onions, 1 chopped, 1 quartered 

3 carrots, 2 peeled and chopped (2/3 cup); 1 peeled and cut crosswise into thirds 

Kosher salt and freshly ground pepper 

1 celery stalk, cut crosswise into thirds 

1 dried bay leaf 

1/2 teaspoon black peppercorns 

2 tablespoons kosher fish sauce, such as Red Boat 

3 tablespoons matzo meal 

1 1/2 pounds skinless salmon fillet 

1/2 pound skinless cod fillet, chopped into 1-inch pieces 

1 tablespoon Dijon mustard 

1 tablespoon sugar 

3 tablespoons chopped fresh dill, plus sprigs for serving 

3 large eggs 

Escarole leaves, lemon wedges, sliced mini cucumbers, halved radishes, matzos, for serving

Lemon-Horseradish Sauce

Carrot-Beet Horseradish

Preparation

Heat oil in a large straight-sided skillet over medium. Add chopped onion and carrots; season with salt and cook, stirring occasionally, until very soft, about 10 minutes. Transfer mixture to a bowl; let cool.

Return skillet to medium-high heat (do not wipe clean). Add remaining onion and carrot, celery, bay leaf, and peppercorns; toast until fragrant, about 2 minutes. Add 8 cups water, fish sauce, and 1 tablespoon salt; bring to a boil. Remove from heat. In a small bowl, combine 1/3 cup liquid and matzo meal. Cover skillet.

Meanwhile, slice 1/2 pound salmon into 10 strips, each about 1 inch thick and 2 inches long. Place on a plate, season with salt, cover, and refrigerate. Chop remaining 1 pound salmon into 1-inch pieces. Place chopped salmon and cod in a food processor with chopped-onion mixture, matzo-meal mixture, mustard, sugar, and dill. Add 2 1/2 teaspoons salt and 1/2 teaspoon pepper; pulse until combined. In the bowl of a mixer fitted with the paddle attachment, beat eggs on medium speed until foamy, 1 minute. Add fish mixture; beat until fluffy, about 7 minutes. Cover and refrigerate 1 to 4 hours.

Scoop fish mixture into 10 half-cup balls; transfer to a parchment-lined rimmed baking sheet. With dampened hands, press a salmon strip into each ball, then shape into an oval. Return liquid in skillet to a simmer. With a spoon, gently drop in fish ovals. Remove from heat; cover and let stand 15 minutes. Refrigerate overnight.

Let stand at room temperature about 30 minutes. With a slotted spoon, gently remove gefilte fish. Serve over escarole with lemons, cucumbers, radishes, matzos, and sauces.