My take on gefilte fish strays from tradition, but with delicious results. I like to use mild-flavored whitefish fillets and lighten things up by swapping the typical fish broth used as a poaching liquid for a white wine- and herb-infused French broth called a court-bouillon. I also infuse my gefilte fish with lemon zest, thyme, and oregano, giving it a lovely herbal flavor. Topped with grated horseradish or creamy horseradish herb sauce, it taste just like tradition, but better. — Leah Koenig, Modern Jewish Cooking.
To make ahead, let cool and transfer to a large container. Pour over enough cooled poaching broth to submerge the gefilte fish. Cover the container and refrigerator for at least 2 hours, or up to overnight. Serve cold or at room temperature topped with the herb sauce.
Combine the ingredients in a wide, deep pot set over high heat. Bring to a boil, then turn the heat to medium-low and simmer, partially covered, for 30 minutes. Strain the mixture through a fine-mesh sieve into a large bowl, then return the broth to the pot. Cover and set aside, off the heat. Discard the solids.
Use a mortar and pestle to crush the thyme and oregano. Combine the onion and carrot in a food processor and process until the vegetables are finely chopped, scraping down the sides of the bowl as necessary. Transfer the vegetables to a large bowl. Working in two batches, add the fish to the food processor and process until it is finely chopped and begins to form a ball. Add the fish to the vegetables along with the matzo meal, eggs, lemon zest, thyme, oregano, salt, and pepper, and mix well to combine.
Return the poaching broth to a simmer over medium-low heat. Meanwhile, moisten your hands with water. Scoop out a scant ¼ cup of the mixture and form into an oval that’s 3 inches long. Set aside on a plate and repeat with the remaining fish mixture.
Use a slotted spoon to place the fish balls in the gently simmering broth. Cover and simmer until firm and cooked through, 18 to 20 minutes. (If you cut one in half, it should be opaque at the center.) Remove the gefilte fish from the pot with a slotted spoon and transfer to a serving plate. Serve warm or at room temperature, topped with the horseradish herb sauce.