Ingredients:
2 tablespoons olive oil
5 tablespoons butter
6 cups sliced onions
5 tablespoons flour
2 1⁄2 cups milk
salt and pepper
1 cup grated Swiss cheese or 1 cup Parmesan cheese (or both)
2 lbs cod fish fillets
1⁄2 cup fresh breadcrumb
Directions:
Heat oil and 2 tablespoon of the butter and cook onions over medium heat until soft and golden, stirring often-- about 15 minutes.
Stir in the flour and cook for 2 minutes. Whisk in the milk, bring to a boil, reduce heat and simmer for 15 minutes. Add more milk if sauce is too thick. Season with salt and pepper.
Spread one third of the onion sauce in a casserole and sprinkle with one third of the cheeses. Cover with the fish fillets, then sprinkle with one third of the cheese. Pour the remaining sauce over the fish and sprinkle with the remaining cheese. Top with the fresh bread crumbs and dot with small pats of butter.
Bake in a preheated 400ºF degree oven for about 20 minutes until the casserole is bubbly.
