- 2 pounds (907 grams) salmon fillets
- 1 pound (453 grams) cod, flounder, rockfish, or whitefish
- 3 medium red onions, peeled and diced (about 2 pounds/907 grams)
- 3 tablespoons vegetable or canola oil
- 4 large eggs
- 4 tablespoons matzo meal
- 2 large carrots, peeled and grated
- 4 tablespoons snipped fresh dill, plus more for garnish
- 1 tablespoon salt, or to taste
- 2 teaspoons freshly ground pepper
- 1 teaspoon Dijon mustard
- 2 tablespoons sugar
- Parsley, for garnish
- Horseradish and Beet Sauce
- Have your fish store grind the fillets or pulse them yourself, one at a time, in a food processor or meat grinder. If using a food processor, pulse the fish in short bursts, being careful not to purée the fish—you want some texture. Preheat the oven to 325°F. Grease a 12-cup Bundt pan and fill a larger pan (such as a large Pyrex dish) with 2 inches of hot water.
- In a large pan over medium-high heat, sauté the diced onions in the oil for about 5 minutes, until soft and transparent but not brown. Set aside to cool.
- Put the fish, onions, eggs, 2 cups (470 ml) water, matzo meal, carrots, 4 tablespoons dill, salt, pepper, mustard, and sugar in the bowl of a standing mixer equipped with a flat beater. Beat at medium speed for 10 minutes.
- Pour the mixture into the Bundt or tube pan, then put the pan inside the larger water-filled dish (called a bain-marie). Smooth the top with a spatula. Cover with aluminum foil and bake for 1 hour, or until the center is solid. Remove the Bundt or tube pan from the water dish, then allow the terrine to cool slightly for at least 20 minutes. Slide a long knife around the outer and inner edges of the Bundt or tube pan, then carefully invert the terrine onto a flat serving plate.
- Refrigerate for several hours or overnight. If any water accumulates on the serving dish, carefully drain it away before serving. Slice the terrine as you would a torte and serve as an appetizer, garnished with parsley and dill and served with Horseradish and Beet Sauce. Leftovers keep for up to 5 days.