Cod au Gratin

Based on the website Girl Heart Food

Here's what you need:
3 large cod fillets salt and pepper
2 cups milk
1 tablespoon olive oil
4 tablespoons unsalted butter
4 tablespoons all-purpose flour
1 tablespoon lemon juice
1 3/4 teaspoons dried dill (dill weed)
2 cups shredded cheddar cheese
1 cup fresh bread crumbs

Instructions:
Step 1. Preheat oven to 375 degrees Fahrenheit.

Step 2. Place cod in a casserole dish (about 8-inch x 11-inch or something similar) and sprinkle with 1/4 teaspoon of salt. Set aside until you make the sauce..

Step 3. In a small saucepan on the stovetop, heat milk over low heat just to warm through.

Step 4. Meanwhile, in another saucepan on the stovetop, add butter. Once the butter melts, add flour and stir to form a paste. Cook, stirring often, about 3 to 5 minutes. Slowly add the warmed milk to this (1/2 cup at a time), whisking after each addition until thickened, about 3 to 4 minutes. Sauce mixture should coat the back of a spoon (mixture will be thick).

Step 5. To sauce mixture, add remaining 1 teaspoon of salt, black pepper, lemon and 1.5 teaspoons of dill. Stir to combine. Pour sauce mixture over cod, coating all fish. Stir to ensure mixture is incorporated well.

Step 6. Sprinkle cheddar cheese and croissant crumbs (or regular bread crumbs) on top of sauced fish mixture. Bake in preheated oven for 40 minutes until bubbly and golden brown.

Step 7. Once done, sprinkle remaining 1/4 teaspoon of dried dill over top. Let cool for about 20 to 30 minutes before serving (don't skip this; it allows things to settle)