*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.
**Nutrient information is not available for all ingredients. Amount is based on available nutrient data.
(-)Information is not currently available for this nutrient. If you are following a medically restrictive diet, please consult your doctor or registered dietitian before preparing this recipe for personal consumption.
Layer half the halibut slices in a 9x13-inch baking dish. Mix sour cream and mayonnaise in a small bowl until smooth; spread half the sour cream mixture over halibut. Spread mushroom slices on top, followed by a layer of half the onion slices and half the Cheddar cheese. Repeat layers of halibut, sour cream mixture, onion, and Cheddar cheese. Sprinkle with saltine crackers.
Bake until crackers are browned and fish is easily flaked with a fork, 35 to 40 minutes.