This gluten-free tuna casserole is the perfect comfort food for the whole family! I skip the canned soups to make a homemade sauce with fresh ingredients and use gluten-free pasta as the base. The cheesy gluten-free breadcrumb topping crisps up perfectly in the oven, and the added veggies make it easy to sneak in some extra nutrients. I love how this recipe uses simple, wholesome ingredients and is ready in just 35 minutes—ideal for busy weeknights!

Gluten-Free Tuna Casserole Recipe

I always have a casserole on my weekly meal rotation, and this recipe for gluten-free tuna casserole has always been a family favorite. It’s just as easy to make as our walking taco casserole or sloppy joe tater tot casserole, and it’s just as delicious! I use low-sodium chicken broth, heavy cream, cheddar, and Parmesan cheese to make a creamy, flavorful sauce without canned condensed soup. The gluten-free pasta, sliced mushrooms, and frozen peas round out the dish and remind me of the classic tuna noodle casserole I loved as a kid!

Ingredients

• Gluten-Free Fusilli: I like gluten-free fusilli, but gluten-free rotini pasta also works. They both hold their shape in the casserole and have a similar cooking time.
• Cremini Mushrooms: These are white button mushrooms that have matured for longer before being harvested. They add a meaty texture and earthy taste to the casserole. You can also use button mushrooms if that’s what you have to hand.
• Gluten-Free All-Purpose Flour: Helps to thicken the sauce.
• Heavy Cream: Full-fat heavy cream is best for this recipe. It makes the sauce unbelievably creamy and rich!
• Chicken Broth: Use low-sodium chicken broth to reduce the overall salt level. Not all chicken broths are gluten-free, so be sure to check the label.
• Yellow Onion: Adds lots of flavor to the filling.
• Garlic: I love how the garlic infuses the casserole with flavor. The recipe calls for 1 teaspoon of minced garlic, which is roughly 1 medium-sized clove.
• Extra Virgin Olive Oil: Used to saute the onion, garlic, and mushrooms.
• Seasonings: Pantry staples like Italian seasoning, salt, and pepper are used to season the casserole.
• Cheddar & Parmesan Cheese: Use freshly shredded cheese where possible to get the best melt. Always check the label of pre-shredded cheese for gluten-containing ingredients.
• Tuna: Canned tuna makes this recipe taste just like a classic tuna casserole! I recommend using tuna packed in water or oil.
• Frozen Peas: Frozen peas are convenient and add color to your casserole.
• Gluten-Free Breadcrumbs: Use any brand you like; just make sure they’re gluten-free. 
• Unsalted Butter: Helps the breadcrumb topping to brown nicely in the oven.

Tips and Suggestions

• Check all of your ingredients to ensure they’re gluten-free. Don’t forget to read the cross-contamination warnings on packages as well.
• Don’t overcook the pasta. You want it cooked to al dente only, or else the pasta will become too mushy when mixed with the other ingredients. Al dente pasta should be tender but firm. There won’t be any crunchiness left in the pasta, but it also won’t be super soft.
• Use full-fat heavy cream to get the best results when thickening the sauce.
• When measuring shredded cheddar cheese, don’t be afraid to pack the cheese down into the cup. Going a little overboard on the cheese is better than not having enough. Like people often say, cheese is better measured with your heart.
• If you can’t find low-sodium chicken broth, adjust the amount of added salt in the recipe to taste.

Is Tuna Gluten-Free?

Yes, most canned tunas are gluten-free. The ones packed in water or oil don’t usually have any added gluten-containing ingredients. However, some flavored or seasoned varieties may contain gluten, so always check the label before purchasing.

What Else Can I Add?

There aren’t any hard and fast rules when making casseroles! This gluten-free tuna noodle casserole is a great ‘clear out the fridge’ meal. You can add in any vegetables that need to be used up, like spinach, corn, or green beans. I think different types of cheeses or seasonings, like chives or red pepper flakes, would also be delicious additions.

What to Serve With Gluten-Free Tuna Casserole

This homemade casserole is a complete meal on its own, but I always make a few sides when serving a crowd. Here are some of my favorite options:

• Roasted broccoli, carrots, or Brussels sprouts
• A slice of gluten-free garlic bread
• Crispy sweet potato fries
• A simple side salad
• Gluten-free onion rings with a honey mustard dipping sauce

Storage Instructions

Store any leftovers in a sealed food-safe container in the fridge for up to 4 days. Reheat in the microwave until warmed through, or in the oven at 350°F for about 15 minutes. You can also freeze this GF tuna noodle casserole for up to 3 months, but there’s a good chance the sauce may separate because of the heavy cream. For this reason, I recommend enjoying it when fresh.

More Gluten-Free Casserole Recipes to Try!

• Philly Cheesesteak Casserole
• Gluten-Free Chicken and Dumplings Casserole
• Gluten-Free Green Bean Casserole

How to Make Gluten-Free Tuna Casserole Step-by-Step

Preheat oven to 350°F. Cook 12-ounces gluten-free fusilli to al dente then drain and set aside. In a large frying pan, sauté 1 small diced yellow onion, 8 ounces sliced cremini mushrooms, 2 tablespoons olive oil, and 1 teaspoon minced garlic over medium heat until the onions start to look translucent and the mushrooms have just started to shrink in size.

Add the 2 tablespoons gluten-free all-purpose flour to the frying pan and lightly toss to coat all the vegetables.

Add 2 cups heavy cream, ¾ cup low-sodium chicken broth, ¼ teaspoon salt, and ¼ teaspoon black pepper to the frying pan and whisk well to combine.

Turn the heat down to low-medium and bring to a light simmer. Let simmer for 5 minutes, stirring often, until the sauce starts to thicken.

Remove frying pan from heat then stir in 1 cup of the shredded cheddar cheese (set the remaining ½ cup of shredded cheddar aside for now) and ½ cup shredded Parmesan cheese until the cheese is completely melted.

Stir in 2 6-ounce cans of drained tuna and 1 cup frozen peas into the mixture until well mixed.

Place the al dente cooked pasta into a 9” x 13” baking dish.

Pour the sauce mixture over the pasta in the baking dish and stir well until all of the pasta is coated with sauce. 

In a medium bowl, stir together 1 cup gluten-free breadcrumbs, remaining ½ cup of shredded cheddar cheese, 3 tablespoons melted butter, and 1 tablespoon Italian seasoning together until mixed well.

Sprinkle the breadcrumb mixture evenly over the pasta mixture in the baking dish. 

Bake the gluten-free tuna casserole in the oven for 20 minutes or until the breadcrumbs start to look golden brown. Serve hot.