Easy Tuna Casserole Recipe (20 Minutes!)

The ultimate dump-and-bake dinner- this easy tuna casserole recipe is your answer. Made with only a few simple ingredients, you get a perfectly cheesy tuna bake in just 15 minutes. 

How to elevate a humble can of tuna into something special? This tuna casserole recipe is your answer.

This has been a comforting and delicious way to enjoy tuna fish. It needs little prep and tastes incredible.

Why this recipe works

This casserole may look time-consuming but honestly, it’s a set-and-forget kind of dish.

• It takes canned tuna to the next level. It’s not always easy to make canned tuna taste like something truly delicious. However, when combined with cheese and mayonnaise and baked with more cheese…need we say more?
• 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. 
• 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.
• No noodles. Most tuna casserole recipes call for noodles or pasta but not this one! It makes a fabulous low carb dinner idea. 

Ingredients needed

This easy tuna casserole 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 canned 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. 
• 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. 
• Cheese. I use mozzarella cheese in the tuna mixture and use gruyere to top off the casserole. 
• Spices. Pepper and smoked paprika used in the right amounts don’t overshadow the mild flavor of canned tuna. 

How to make tuna casserole

Cheesy tuna casserole is easy to make: just remember to choose an appropriate size baking dish.

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. Add pepper, smoked paprika, and salt to taste. Mix until fully combined. When all ingredients are mixed, fold in the shredded mozzarella cheese. 

Assemble: Transfer the tuna mixture into the baking dish and top with sliced or shredded gruyere cheese.

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

Tips to make the best recipe

• 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.

Recipe variations

Add crispy elements. Sprinkle the casserole with a breadcrumb and butter mixture for a golden and crispy crust that will contrast beautifully with the creamy tuna mixture.

Use a blend of cheeses. Use a combination of different cheeses to make this tuna bake taste even better. Smoked cheddar, gouda, Asiago, and Monterey Jack will work well for this.

Add some spice. Add mild heat to this casserole by using pickled or fresh jalapenos. You can also stir through some hot sauce, red pepper flakes, or even sriracha.

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 fridge 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.

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