Here is what I did

preheat oven to 375 degrees fahrenheit
melt 4 tablespoons butter in 2 1/2 quart baking dish

Finely slice (1/16" thick) one medium sweet onion and bisect to not have rings but 1/4 circles and add to melted butter

Cut fish ((one pound of Halibut (one can use any fish) in this case)) to strips approximately 1/2" X 1/2" by the length of the fillet but not longer than the baking dish.....use this fish to cover the onion. Sprinkle 1/2 tablespoon lemon juice over the fish.

NOTE: The fish to be thoroughly patted dry with paper towels....I destroyed a dozen paper towel sheets doing this.....dry is good in this case

Mix 1 cup sour cream and 1 cup mayonnaise, 1 tsp dill seed, 1 tsp dill weed and 1/2 tsp black pepper fine grind....add to the baking dish thoroughly covering the fish.

Bake 30 minutes at 375 degrees uncovered

remove from the oven and add 6 ounces shredded mild cheddar cheese and bake another three minutes.

It's now dinner time.....if you don't like this see a doctor as there's something radically wrong with your taste buds.

Wish they weren't asking the troy ounce price of gold for a halibut filet these days. Looks good!

I brought the fillets from a 50 pound halibut last July. Wish I still had some.
I’ll get more in July and try this.

Interesting.
I don't think I would have ever imagined sour cream or cheese and possibly Mayo in conjunction with fish.

Gotta find some fish to try this with.

TCL, you should find some Norwegians .Herring in cream sauce is a common appetizer. There are fine soups with cod fish or mixed fish with sour cream !! Try it !