The Jewish Sabbath is honored and enhanced with meals of delicious and abundant food. Challah, fish, meats, and sumptuous side dishes are served both Friday night and Saturday noon. Among Eastern-European Jews, gefilte fish is the traditional fish appetizer served on the Sabbath, the New Year, and Passover. Originally the ground fish mixture was actually put back into the skin of the fish for cooking, giving rise to the name "filled" or gefilte fish.
To improve on the traditional carp or carp and whitefish mixture, I experimented for several years with pike, trout, salmon, cod, and even halibut. I serve this gefilte fish recipe at Passover and the less ambitious gefilte fish loaf during the rest of the year.
I use a food processor to grind the fish, but you can also chop it in a chopping bowl or have the fish monger grind it for you. Put all ingredients, as they are ground, in a very large bowl or tub. (For Passover, I use a perfectly clean dish tub. It's the only thing large enough for all the ingredients to be thoroughly mixed.)
Beat water, pepper, salt, eggs and oil in a mixer or in the food processor--this should be almost mousse consistency. Add this to the fish mixture in the large bowl or tub and mix thoroughly. (If you prefer, you can do all of this in batches in a food processor.)
With moist hands, shape 1/3 to 1/2 cup of mixture into balls, and carefully place in the simmering stock. Be cautious that you don't disturb existing pieces, but you can crowd and fill the stock with fish balls. Distribute fish in the two pots, cover, and simmer for 1.5 hours.
Let the fish cool a bit, covered. Then carefully remove fish and vegetables to storage containers. Strain the liquid over the fish. Remove the carrot pieces and onions and add to the fish. Throw away the bones, and enjoy a "lunch" of the bits of fish in the strainer.
Store the fish for up to 7 days, well refrigerated. Serve mild or hot prepared horseradish on the side.
Source: Ruth's Kitchen