This Fish Casserole is a simple baked dinner made with tender haddock, a creamy sour cream sauce, vegetables, and melted Gouda cheese. It's comforting without being heavy and comes together with straightforward ingredients and minimal prep.
A Quick Look at the Recipe
✅ Recipe Name: Fish Casserole
🕒 Ready In: ~45 minutes
👪 Serves: 4-6 servings
🍽 Calories: ~390 calories (estimated)
🥣 Main Ingredients: Haddock, sour cream, bell peppers, tomatoes, Gouda cheese
📖 Dietary Info: Gluten-free; high-protein
👌 Difficulty: Easy - simple stovetop sauce, baked in one dish
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Instead of relying on canned soups or overly rich sauces, this recipe builds flavor with sautéed vegetables, warm spices, and a lightly creamy base. Baking the fish directly in the sauce keeps it moist while the cheese adds just enough richness on top.
If you like cozy, baked dinners, try a few of our favorites like Baked Greek Chicken, Spaghetti Squash Casserole, and Dutch Oven Pot Roast. They're the same kind of simple, family-style meals that are great to keep in rotation.
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Why You'll Love this Fish Casserole:
Comforting and familiar: Creamy sauce, tender fish, and melted cheese make this an easy, cozy dinner option.
Simple ingredients: Everything comes together with basic vegetables, pantry spices, and frozen fish.
No canned soups: The sauce is made from scratch for better flavor and texture.
Easy to prep ahead: The sauce can be made in advance, then baked when you're ready.
Family-friendly: Mild flavors and a creamy finish make this approachable for all ages.
Key Ingredients:
- haddock. A mild, flaky white fish that works perfectly in this casserole. You can substitute with cod, tilapia, or any other firm white fish.
- tomatoes. Fresh, diced tomatoes add acidity and balance the richness of the dish. Canned diced tomatoes (drained) can work in a pinch.
- bell peppers. A mix of red and green peppers adds sweetness and crunch. You can swap them for yellow or orange bell peppers for a different flavor profile.
- sour cream. Adds creaminess without the need for heavy cream. For a tangier flavor, you can use Greek yogurt as a substitute.
- gouda cheese. Creates a creamy, slightly sweet topping. Swiss or mozzarella can be substituted for a different texture and taste.
Scroll to the recipe card at the bottom of this page for exact quantities.
Easy Substitutions & Variations:
- Swap the fish: Cod or pollock can be used in place of haddock with similar results.
- Change the cheese: Cheddar, Swiss, or mozzarella work well if you don't have Gouda on hand.
- Use Greek yogurt: Plain Greek yogurt can replace sour cream for a slightly tangier, lighter sauce.
- Add extra vegetables: Zucchini, spinach, or mushrooms can be stirred into the sauce for more veggies.
- Adjust the seasoning: A pinch of cayenne or extra paprika can add warmth if you like a little heat.
How to Make Fish Casserole:
- Preheat the oven to 350 degrees. Grease a 9x13 baking dish and set aside.
- In a large skillet, heat a tablespoon of olive oil on medium heat and cook onion, tomatoes, bell peppers, coriander, thyme, and paprika for 5-10 minutes.
- Add the sour cream and cook until heated through. Season with salt and pepper to taste.
- Arrange the haddock pieces in a casserole dish, then pour the sauce over the haddock.
- Top with the grated cheese and bake for 25 minutes. Garnish with fresh parsley and serve.
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Recipe Notes & Tips:
- Prep the Fish: If using frozen haddock, make sure to thaw it completely and pat it dry with paper towels to remove excess moisture before baking. This helps prevent a watery casserole.
- Sauté for Maximum Flavor: Cooking the onions, tomatoes, and bell peppers first allows their flavors to develop and blend before adding them to the casserole.
- Add the Sour Cream Off Heat: To prevent curdling, stir in the sour cream after removing the skillet from heat rather than cooking it for too long.
- Even Cooking: Arrange the fish in a single layer in the baking dish to ensure even cooking and allow the sauce to coat each piece evenly.
- Golden Brown Topping: For a crispier, more golden top, broil the casserole for the last 2-3 minutes of baking.
- Serving Suggestions: We love serving this casserole with Balsamic Brussels Sprouts or Kale Apple Salad.
How to Store:
Refrigerate: Store leftover fish casserole in an airtight container in the fridge for 3-4 days. Let it cool completely before storing to prevent excess moisture buildup.
Reheating: To maintain moisture, reheat in a 325°F oven, covered with foil, until heated through. This prevents the fish from drying out. If using a microwave, reheat in short intervals to avoid overcooking.
Freezing: Freezing is not recommended due to the dairy-based sauce and the texture of the fish. Freezing may cause separation and a less desirable texture upon reheating.
Fish Casserole FAQs:
Yes. Just make sure the fish is fully thawed and patted dry before adding it to the casserole so the sauce doesn't become watery.
Mild, flaky white fish like haddock, cod, or pollock work best because they bake evenly and absorb the sauce well.
The fish should be opaque and flake easily with a fork. A food thermometer should read 145°F at the thickest part.
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Fish Casserole
Ingredients
- 1 pound frozen haddock, thawed
- 1 cup sour cream
- 1 onion, diced
- 2 tomatoes, diced
- 1 red bell pepper, diced
- 1 green bell pepper, diced
- 1 teaspoon ground coriander
- ½ teaspoon dried thyme
- ½ teaspoon paprika
- 1 cup gouda cheese, shredded
Instructions
- Preheat the oven to 350 degrees. Grease a 9x13 baking dish and set aside.
- In a large skillet, heat a tablespoon of olive oil on medium heat and cook onion, tomatoes, bell peppers, coriander, thyme, and paprika for 5-10 minutes.
- Add the sour cream and cook until heated through. Season with salt and pepper to taste.
- Arrange the haddock pieces in a casserole dish, then pour the sauce over the haddock.
- Top with the grated cheese and bake for 25 minutes. Garnish with fresh parsley and serve.
Nutrition
Notes
- Prep the Fish: If using frozen haddock, make sure to thaw it completely and pat it dry with paper towels to remove excess moisture before baking. This helps prevent a watery casserole.
- Sauté for Maximum Flavor: Cooking the onions, tomatoes, and bell peppers first allows their flavors to develop and blend before adding them to the casserole.
- Add the Sour Cream Off Heat: To prevent curdling, stir in the sour cream after removing the skillet from heat rather than cooking it for too long.
- Even Cooking: Arrange the fish in a single layer in the baking dish to ensure even cooking and allow the sauce to coat each piece evenly.
- Golden Brown Topping - For a crispier, more golden top, broil the casserole for the last 2-3 minutes of baking.
jum says
really good, but 45 minutes is way to long. my fish was over cooked. is that time correct
Kaeleigh Pugliese says
So sorry that is not correct it should be 25 minutes!
jim says
ah yes much better lol
Judy says
The ingredients say "shredded" cheese and the instructions say "grated" cheese.
Jeanette says
Absolutely delicious. I added a sprinkling of smoked paprika as well.
Marie says
I love smoked haddock and this was a very delicious recipe!! Will be added to my dinner rotation for sure.