Easy Tuna Casserole Recipe

This easy tuna casserole recipe is the ultimate dump-and-bake dinner. Made with only a few simple ingredients, you get a perfectly cheesy tuna bake in just 20 minutes.

I love cooking with canned tuna. It’s affordable, always available, and let’s be real- everyone has a can or ten of it in the pantry at any one time.

On regular rotation in our household are tuna patties and tuna croquettes but when the family is craving something baked and hearty, nothing beats a cheesy tuna casserole. 

Table of Contents

1. Why this recipe works
2. Ingredients needed
3. How to make tuna casserole
4. Recipe tips and variations
5. Storage instructions
6. More casserole recipes you’ll enjoy
7. Frequently asked questions 
8. Easy Tuna Casserole Recipe (Recipe Card)

Why this recipe works

• It takes canned tuna to the next level. It’s not always easy to make canned tuna taste like something truly delicious (I mean, hello tuna tartare, tuna carpaccio, and seared ahi tuna). However, when combined with cheese and mayonnaise and baked with more cheese, it’s pretty much perfection. 
• Easy and quick. As everything is baked in one dish, it takes only a few minutes to prep it and around 15 minutes to bake. I sometimes even prep it IN the dish so I only have one thing to clean up at the end. 
• Perfect texture and flavor. The texture is thick and creamy and morsels of melty cheese throughout. If you are worried about the potential fishy taste, don’t be- the cheese and mayo do a fabulous job of covering it up.

What I love about this recipe is that it has NO noodles and NO cream of mushroom soup. These are two typical ingredients in most tuna noodle casserole recipes but not this one. Don’t fret though- it’s every bit as hearty and creamy as you’d expect.

Ingredients needed

This easy tuna casserole recipe really lives up to its name and besides the tuna, cheese, and seasonings, there isn’t much else that is needed to make. Here. is what you’ll need:

• Tuna. Use solid white albacore tuna in water for a light and flaky texture. Avoid tuna that is flavored or packed in oil, as it will make the casserole greasy. 
• Mayonnaise and sour cream. These two condiments taste so much better when mixed together. Use both to provide extra creaminess for this casserole. Don’t use one or the other or else you’ll be left with a super-rich casserole (all mayo) or super stodgy one (all sour cream). 
• Cauliflower. Adds some bulk and nutrients to the dish. This is completely optional, and you can omit it if you like. If using cauliflower, please cook it beforehand (steaming, air frying, or roasting works). 
• Onion. Use finely chopped green onions for a refreshing and mild onion flavor.
• Mustard. Go with Dijon mustard for a tangy and slightly spicy flavor. It balances out the creaminess of the mayo and sour cream. 
• Cheese. I use mozzarella cheese in the tuna mixture and use gruyere to top off the casserole. You can use any cheese that melts well, including cheddar cheese or parmesan cheese. 
• Spices. Pepper and smoked paprika used in the right amounts don’t overshadow the mild flavor of canned tuna. I sometimes add some garlic powder too.

How to make tuna casserole

As mentioned earlier, this casserole is so easy and needs little prep time, thanks to the oven working its magic! Ready to whip one up? 

Step 1- Prepare the tuna mixture: Flake the tuna and add it to a mixing bowl, along with the cooked cauliflower. Next, add the mayonnaise, sour cream, chopped green onion, and Dijon mustard and stir well. Add pepper, smoked paprika, and salt to taste. Mix until fully combined. When all ingredients are mixed, fold in the shredded mozzarella cheese.

Step 2- assemble: Transfer the tuna mixture into the baking or casserole dish and top with sliced or shredded gruyere cheese.

Step 3- Bake: Bake for 15-20 minutes or until the cheese is melted and golden brown. Remove from the oven and serve warm. 

Recipe tips and variations

Do not over-bake. The creamy and rich texture is imperative to this dish, so do not overbake. Once the cheese has nicely melted, it’s fine to be removed from the oven.

Flake the tuna into larger chunks. If you flake it into very small pieces, the tuna mixture will turn into mush when you mix the canned fish with the rest of the ingredients.

Grate the cheese by hand. For the best melt and flavor, always shred the cheese using a grater. The extra effort is worth it.

Add a crumb topping. Sprinkle the casserole with a breadcrumb and melted butter mixture for a golden and crispy crust that will contrast beautifully with the creamy tuna mixture. Other delicious options include crushed potato chips, ritz crackers, or panko bread crumbs. 

Use different vegetables. We prefer cauliflower for its mild flavor but definitely amp up the casserole with other vegetables. Peas and corn always work well, as do some finely diced celery and carrots.

Make it healthier. For a healthy tuna casserole, swap out the sour cream for Greek yogurt and use low-fat mayonnaise.

Storage instructions

To store. Place leftovers in an airtight container in the refrigerator and it will be good for up to 4 days. 

To freeze. Once the casserole has cooled, place portions of it in a shallow container and store it in the freezer for up to 6 months.

To reheat. The best way to reheat any casserole is in the oven, covered with tinfoil. You can also microwave small servings of it.

More casserole recipes you’ll enjoy

• Squash casserole
• Zucchini casserole
• Philly cheesesteak casserole
• Chicken casserole
• French onion chicken casserole
• Spaghetti squash casserole

Frequently asked questions