Gluten-Free Fish Casserole {Freezer Meals}

Nothing says comfort food better than a big old helping of homemade Gluten Free Fish Casserole. This simple dish can be made ahead of time and is beyond very easy to whip up into the most creamy, filling and decadent homemade Fish Casserole.

This creamy baked fish casserole is a classic dish perfect for Sunday lunches with the family, a filling summer lunch, easy weeknight suppers and special occasions such as Easter, Christmas and Father’s Day.

Plus, there are a couple of things different about this healthy fish casserole;

1. First, it is gluten-free. Yeap, this recipe  uses cornstarch (cornflour) instead of flour to make the roux that thickens up the casserole sauce.
2. And second, I have used a variety of fish to complete this Healthy Seafood Casserole, rather that just sticking to one fish or the other. This is one of those ‘the more the merrier’ kinda recipes.

So, have I tempted you yet? Then go grab your ingredients, come back here and let me show you……

How To Make Fish Casserole

• Step 1. Boil and mash the potatoes with some plant-based milk and dairy-free butter, then set aside.
• Step 2. Sauté green onions in melted butter before adding cornstarch.
• Step 3. Slowly whisk in the plant-based milk, then bring to a rolling simmer, stirring continuously until the sauce is thick.
• Step 4. Switch off the heat, then stir in mustard, nutmeg, anchovies, fish casserole mix, baby spinach and peas before transferring to a baking dish.
• Step 5. Top with mashed potatoes and bake for 25 min in the hot oven until golden and the mixture is bubbling.
• Step 6. Serve the baked fish casserole warm.

Oven Baked Fish Casserole Recipe Tips

A few tips to make sure your Oven Baked Fish Casserole Recipe turns out super awesome:

• If you are starting with whole fish ,then make sure to cut into similar-sized chunks so they cook at the same time.
• If you have less fish than the recipe calls for, you can bulk up your fish casserole with extra veggies.

What Type Of Fish To Use For Fish Casserole

TBH, you can use your favorite type of fish. You can also buy whole fish and then chop into suitable size pieces. However, the easiest thing to do is go to your local market and buy some fish pie mix, which comes with a nice variety of fish.

Fish Casserole Variations

• Feel free to add more quick-cooking vegetables like green beans and sweetcorn.
• You can also add shrimp to the chopped fish mix.
• Try using mashed sweet potato instead of regular mashed potatoes.

Fish Casserole With Pastry

If you prefer, you can make this a fish pie with pastry. To do so, simply skip the mashed potato and cover the fish casserole mix with puff pastry and then bake. Just make sure you are using a gluten-free pastry.

Cheesy Fish Casserole

If you want to upgrade this to a cheesy seafood casserole you can. Simply take the casserole out after about 15 mins and top with lots and lots and lots of cheese. Then return to the oven till cook time is done.

Can You Freeze Fish Casserole?

Yes, you can freeze fish casserole. Just assemble, and instead of cooking right away, cover tightly and freeze. If you are going to freeze it, then start with fresh fish rather than frozen fish. A perfect make-ahead meal prep solution!

Can You Reheat Fish Casserole?

Yes you totally can reheat your homemade fish casserole. Just follow these easy steps:

1. Preheat the over to 275F / 140C.
2. Add a splash of milk or water to the casserole and cover with foil.
3. Reheat for about 12-15 minutes till warmed through.

What to Serve With Fish Casserole

This baked fish casserole make a great meal by itself but if you want to stretch it out a little bit, then feel free to serve any of  these sides:

Instant Pot Steamed Broccoli.

Instant Pot Glazed Carrots.

Cucumber Tomato Salad.

Easy Spinach Salad.

More Gluten Free Fish Recipes

Want more gluten-free fish recipes? Then try these tasty dishes:

Crispy Air Fryer Fish.

Juicy Air Fryer Salmon Fillets.

Air Fryer Salmon Patties.

Thank you for reading my gluten free Fish Casserole recipe post. And please come visit again as I continue dreaming up recipes, traditional African recipes, African fusion recipes, Sierra Leone recipes, travel plans and much more for you. Thanks for supporting Recipes from a Pantry, UK food blog.

Originally published June 2018. Republished October 2019.

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Print Recipe

4.91 from 10 votes

Easy Fish Casserole

This simple dish can be made ahead of time and is beyond very easy to whip up into the most creamy, filling and decadent homemade Fish Casserole.

Prep Time5 minutes mins

Cook Time40 minutes mins

Total Time45 minutes mins

Course: Main Course

Cuisine: gluten free, Western

Servings: 4

Calories: 304kcal

Author: Bintu Hardy

Ingredients

• ▢ 2 lbs (1kg) potatoes, peeled and cut chunks
• ▢ 4 tbsp dairy-free butter divided
• ▢ 2 cups (500ml) plant-based milk 1/4 cup for mashed potatoes; 1 3/4 cups for casserole.
• ▢ 2 tsp olive oil
• ▢ 2 green onions finely sliced
• ▢ 4 tsp (20g) cornstarch
• ▢ 1 tsp Dijon mustard
• ▢ 1/4 tsp ground nutmeg
• ▢ 4 anchovy fillets finely chopped
• ▢ 1 1/2 cups (400g) fish pie mix
• ▢ 2 1/2 cups (75g) baby spinach roughly chopped
• ▢ 1/2 cup (75g) frozen peas

Instructions

• Preheat the oven to fan-assisted 180C / 200C / 400F / gas 6.
• Add the potatoes into some salted boiling water, bring back to the boil, reduce to a simmer cook until tender.
• When done, drain, let cool for a few mins and mash with a 4 tbsp of milk and 2 tbsp of dairy-free butter and set aside.
• Melt butter in a sauce pan, add green onions and cook for a min, then add in cornstarch and cook for a min.
• Slowly whisk in the milk, then bring to a rolling simmer while stirring continuously (to avoid any lumps) for 3 - 4 mins until the sauce is thick.
• Switch off the heat, then stir in mustard, nutmeg, anchovies, fish pie mix, baby spinach and peas before transferring mix to a baking dish.
• Top with the mashed potatoes and bake for 25 mins in the hot oven until golden and the mixture is bubbling.

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Notes

Fish Casserole Tips

• If you are starting with whole fish, then make sure to cut into similar-sized chunks.
• Try adding some shrimp to the fish pie mix.
• If you have less fish than the recipe calls for, you can bulk up your casserole with extra veggies.
• Feel free to add more quick-cooking vegetables like green beans and sweetcorn.

Nutrition

Calories: 304kcal | Carbohydrates: 15g | Protein: 26g | Fat: 15g | Saturated Fat: 4g | Cholesterol: 63mg | Sodium: 185mg | Potassium: 663mg | Fiber: 1g | Sugar: 8g | Vitamin A: 2240IU | Vitamin C: 15mg | Calcium: 194mg | Iron: 1.5mg