Go Back
Individual au gratin dish filled with baked haddock in a rich cream sauce

Baked Haddock au Gratin

This Baked Haddock au Gratin dresses up mild white fish fillets with a delectable cream sauce topped with breadcrumbs and cheddar cheese. Serve with rice or choice of potato and side vegetable(s).
Course Main Course
Cuisine Canadian
Keyword baked haddock au gratin, fish, haddock, seafood
Servings 2
My Island Bistro Kitchen Barbara99


  • 2 haddock fillets, each apx. 5-6 oz (fresh or thawed, if frozen)
  • Garlic salt (apx. ½ tsp or to taste)
  • Freshly ground black pepper
  • 1/3 cup chicken stock
  • 1/3 cup whipping cream (36% MF)
  • ¼ cup milk
  • 1 tsp Dijon mustard
  • 1 tbsp butter, melted
  • 1½ - 2 tbsp butter
  • tbsp finely chopped onion
  • tbsp finely chopped celery
  • 3 tbsp finely chopped red pepper
  • 1/3 cup sliced white button mushrooms (about 1 oz)
  • 2 tbsp all-purpose flour (or gluten-free 1-to-1 baking flour, if required)
  • 1/3 cup fine breadcrumbs (gluten-free, if required)
  • tbsp finely grated Parmesan cheese
  • ½ tbsp butter, melted
  • 1/3 cup grated old or medium Cheddar cheese
  • Paprika (optional)
  • Green onions and/or slices of orange or lemon for garnish (optional)


  1. In small bowl, combine the chicken stock, whipping cream, milk, Dijon mustard, and 1 tbsp melted butter. Set aside.
  2. Chop and measure vegetables and grate cheeses.
  3. Preheat oven to 350°F.
  4. Grease two individual-sized au gratin dishes (or a small shallow baking dish just large enough to arrange the fillets in a single layer). Sprinkle fish fillets with garlic salt and pepper. Arrange one fillet in each au gratin dish or single layer if using one baking dish for the two fillets. Note, in order to get the fish fillet to fit in the single au gratin dishes, an end of each fillet may need to be cut off and arranged alongside fillet in au gratin dish. Set aside.

  5. Melt 1½ - 2 tbsp butter in saucepan over medium-high heat. Add the onions, celery, red pepper, and mushrooms. Cook the vegetables just until they are barely tender, stirring frequently (apx. 3 minutes).
  6. Sprinkle flour over the vegetables and stir to combine. Cook for a few seconds, stirring to prevent scorching, then reduce heat to medium low and gradually add the whipping cream and chicken stock mixture. Stir constantly to prevent scorching. Continue cooking until sauce starts to thicken, apx. 1 -2 minutes. Add the Parmesan cheese and stir until melted, about 1 minute longer or until sauce is thickened to desired consistency.

  7. Spoon sauce equally over each fillet, covering all areas of the fish completely. Combine the breadcrumbs and the ½ tbsp melted butter. Sprinkle mixture equally over fillets. Place au gratin dishes on foil-lined rimmed baking sheet in case sauce should bubble over. Bake for apx 20-24 minutes, or until breadcrumbs are browned, sauce is bubbling, and fish is thoroughly cooked and flakes easily when tested with a fork. Note that baking times may vary due to size and thickness of fillets.

  8. Sprinkle cheddar cheese over each fillet and return to oven for 1½ - 2 minutes, just until cheese is melted.
  9. Let fish stand for 5-10 minutes to allow sauce to set before serving. Sprinkle each fillet with paprika and garnish with sliced green onions and an orange or lemon slice, if desired.
  10. Serve with choice of potato or rice, and a favorite side of vegetable(s), steamed or stir-fried.

Recipe Notes

Yield: 2 servings