Why You’ll Love This Recipe

This dish combines flaky cod with a luscious, cheesy sauce and a crispy topping, delivering warmth and indulgence perfect for family dinners or special occasions. The use of potato chips adds an unexpected, delightful crunch that pairs beautifully with the creamy, savory gratin.

Ingredients

2 lbs fresh boneless cod loins*
¼ cup butter
½ small onion, finely chopped
2 garlic cloves, pressed or minced
¼ cup corn starch (or potato starch if needed)
1 tablespoon Dijon mustard
¼ cup dry white wine
2 ¼ cups milk
⅔ cup shredded Parmesan cheese
1 cup shredded cheddar cheese
2 teaspoons dried summer savory
Salt and pepper, to taste
1 small bag plain potato chips, crumbled

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

Directions

Preheat oven to 375°F (190°C).
Butter a large baking dish and arrange the cod loins evenly in the dish. Season with salt and pepper.
In a saucepan, melt butter over medium heat. Add finely chopped onion and minced garlic; sauté until translucent and fragrant, about 3-4 minutes.
Stir in corn starch and Dijon mustard until well combined. Gradually whisk in white wine and milk, stirring constantly to avoid lumps.
Cook the sauce until it thickens, about 5-7 minutes. Remove from heat and stir in Parmesan and cheddar cheese until melted and smooth. Add dried summer savory and adjust salt and pepper to taste.
Pour the cheese sauce evenly over the cod loins in the baking dish.
Sprinkle the crumbled potato chips over the top to create a crunchy crust.
Bake for 25-30 minutes or until the sauce is bubbly and the topping is golden brown.
Remove from oven and let rest for 5 minutes before serving.

Servings and Timing

Servings: 6
Prep time: 15 minutes
Cook time: 30 minutes
Total time: 45 minutes

Variations

Breadcrumb Topping: Substitute potato chips with seasoned panko breadcrumbs for a different crunch.
Herb Mix: Add fresh thyme or parsley to the sauce for extra flavor.
Spicy: Add a pinch of cayenne pepper or smoked paprika to the cheese sauce.
Vegetable Boost: Add steamed broccoli or peas beneath the fish before pouring the sauce.

Storage/Reheating

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven until warmed through to maintain texture.

FAQs

Can I use frozen cod?

Yes, thaw completely and pat dry before cooking.

Can I use other fish instead of cod?

Firm white fish like haddock or halibut work well.

Is this dish gluten-free?

Yes, if using corn starch and plain potato chips without gluten additives.

Can I prepare the sauce ahead of time?

Yes, make the sauce in advance and reheat gently before baking.

What if I don’t have dry white wine?

Use chicken broth or white grape juice as a substitute.

Can I add more cheese?

Yes, feel free to increase Parmesan or cheddar for extra cheesiness.

How do I prevent the sauce from curdling?

Heat the sauce gently and avoid boiling once cheese is added.

Can I freeze leftovers?

Freezing is not recommended as texture may change.

What side dishes pair well?

Serve with a green salad, roasted vegetables, or steamed rice.

How do I get a crispy topping?

Use crushed potato chips or toasted breadcrumbs and bake uncovered.

Conclusion

Traditional Cod Au Gratin is a rich, comforting dish that combines tender fish with a creamy cheese sauce and a crunchy potato chip topping. Easy to prepare and full of flavor, it’s a perfect meal for family dinners or cozy nights in.