Halibut Olympia with Parmesan and Green Onions

An Alaska fish bake with a simple creamy cover

Dry the fish, divide the onions evenly, and check the thickest fillet first

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Halibut Olympia places halibut fillets between two layers of chopped green onions, giving the mild fish a fresh savory base and top. The arrangement is simple enough for a weeknight but generous enough to bring to the table in its baking dish.

The topping blends sour cream, mayonnaise, and grated Parmesan cheese into a smooth layer. As it heats, the mixture protects the halibut’s surface and becomes lightly set while the fish cooks underneath.

Dry the fillets and prepare an even onion layer

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Preheat the oven to 400°F. Blot the halibut with paper towels so the topping sits against the fish instead of sliding on excess moisture. Run a fingertip gently over each fillet and remove any pin bone you find.

Use a chef’s knife on a cutting board to chop the green onions into small, even pieces. Half goes beneath the fish and half goes above it, so keeping the pieces similar helps the onion flavor reach the full dish instead of gathering in one corner.

Mix the topping until the Parmesan is evenly dispersed

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Use measuring cups for every topping component. When starting with a block, grate the cheese on a box grater so it melts into the dairy mixture without leaving large firm pieces.

Combine everything in a medium mixing bowl and use a whisk until no plain streaks of sour cream or mayonnaise remain. The Parmesan should be visible throughout the mixture, but there is no need to beat in air; a cohesive spread is the goal.

Arrange one fish layer and cover it from edge to edge

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Scatter the first half of the onions over a large baking dish, then set the fillets over them without overlapping. Place thicker pieces near the outside if your dish tends to heat strongly around its edges, and leave a little room between portions when possible.

Add the remaining onions and spread the creamy mixture with a rubber spatula. Cover the top of each fillet rather than filling every open space in the dish. An even layer helps similarly thick pieces cook at a similar pace and gives each serving its share of Parmesan.

Use the thickest fillet to decide when the dish is done

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Begin checking at fifteen minutes. Slide an instant-read thermometer into the thickest part of the largest fillet; it should reach 145°F and flake easily. Thinner portions may be ready sooner, so lift them out rather than leaving every piece in for the full twenty minutes automatically.

Use oven mitts to move the dish to a protected surface and let it stand for three minutes. A serving spatula can slide beneath both fish and the softened onion base, preserving the creamy top as the portion moves to the plate.

Serve moderate pieces with bright, simple sides

Eight moderate servings make sense for sharing this rich preparation with family or friends, especially when the halibut is joined by vegetables, rice, or roasted potatoes. Bring the baking dish to the table after its short stand and let each person choose a thicker or thinner portion according to appetite. Crisp greens, steamed beans, or a cabbage salad offer freshness against the creamy topping and keep the plate from needing another heavy sauce. Keep any extra Parmesan off the table at first so the balanced onion-and-cheese layer can speak for itself, then pass sides and settle in for the meal. The fillets lift cleanly enough for a relaxed shared dinner, and smaller portions leave room for seconds if the group is especially hungry.

Tell us which sides you served, or ask a question about adapting the bake for fillets of different thicknesses. Leave a comment.