Skip to Content

Tuna Broccoli Casserole

Craving a simple and delicious meal? Then this easy tuna broccoli casserole is for you! The recipe combines flaky tuna, tender broccoli, sweet cherry tomatoes, and melty cheese in a creamy dish that is ready in 35 minutes.

This easy tuna casserole is right up there with chicken noodle soup, mac and cheese, and hamburger helper when it comes to comfort food.

close-up of tuna broccoli casserole with spoon and part removed.

Cheesy broccoli tuna casserole

Creamy casseroles are a family favorite at our house. They’re classic comfort food that always hits the spot, and this tuna broccoli casserole is no different!

It’s a lightened-up version of classic tuna pasta casserole. You get tender broccoli, savory tuna, juicy cherry tomatoes, and a decadent cheese topping baked into pure magic.

The recipe takes about 35 minutes from start to finish. Easy and effortless!

Whether you make this delicious meal for a weeknight family dinner or take it to a potluck, this easy tuna casserole is sure to impress.

Do you love hearty casserole recipes? Then try our veggie ground beef casserole, chicken spaghetti, and gnocchi bake next!

tuna broccoli casserole ingredients.

Ingredients

  • 1 bunch fresh broccoli – That’s 2 to 3 heads. Cut them into florets. To save time, you can also opt for frozen broccoli florets (12 oz). No need to thaw. Just add 2 minutes to the cooking time.
  • 1 large onion, chopped – makes the casserole flavorful. To save time, use 1/2 tablespoon onion powder.
  • 2 garlic cloves, finely minced – Fresh garlic tastes best, but 1/2 teaspoon garlic powder will work in a pinch.
  • 2 tablespoons olive oil – to sauté the onion and garlic for an aromatic base.
  • 3 x 5 oz cans tuna – Buy light tuna in water or buy Albacore tuna if you want to splurge.
  • 7.5 oz crème fraiche – makes the creamy base of the dish. It tastes rich and slightly tangy. You can find it in the dairy section at Walmart, Trader Joe’s, Kroger, and other supermarkets.
  • 1 cup cherry tomatoes, halved – They add a pop of color and fresh taste
  • 6 oz mozzarella cheese, sliced – creates a rich, melty cheese topping. I love sliced mozzarella, but 1 cup of shredded mozzarella is fine too..
  • 1 cup shredded sharp white cheddar cheese – If you have the time, shred the cheddar yourself from a block of cheese. Otherwise, grab a bag of pre-shredded cheddar.
  • Salt + pepper
  • a few fresh basil leaves – for garnish. This is optional.
broccoli tuna casserole in a baking dish.

Variations

  • Cheese: You can top the casserole with pretty much any melty cheese you have and like. Havarti, Jack cheese, Swiss cheese, gouda, parmesan, and Emmental work great here.
  • Mascarpone: Mascarpone is an excellent alternative for creme fraiche in this recipe. I don’t recommend cream cheese in this recipe because I found it curdles in the sauce.
  • Alfredo sauce: Sub the creme fraiche with a jar of alfredo sauce for an extra creamy tuna broccoli casserole.
  • Salmon: Not a fan of tuna? Swap in canned salmon or cooked salmon filets!
  • Cauliflower: Cauliflower is a great stand-in for broccoli in this recipe.
  • Other veggies: You can modify this casserole with all kinds of veggies in addition to or as a substitution for broccoli. Think peas, carrots, zucchini, or bell peppers.

Instructions

1. Prep work

Preheat your oven to 400°F / 200°C / gas mark 6. Spray a 9×13-inch / 23×33 cm baking dish with cooking spray. Set aside.

step 2 cook broccoli.

2. Cook broccoli

Bring a large saucepan of water to a simmer. Add the broccoli and 1 teaspoon salt. Cook uncovered for 5 minutes, until crisp-tender. Drain and set aside.

Don’t cook the broccoli all the way: You want the broccoli just tender and slightly undercooked. The broccoli will continue to soften as you bake the casserole.

Drain well to avoid a watery casserole: I like to dump the cooked broccoli into a colander in the sink to drain while I sauté the onion and garlic. To save on dishes, sauté the aromatics in the same saucepan or pot you cooked the broccoli in.

step 3 sauté aromatics.

3. Sauté aromatics

In the same saucepan, heat the oil over medium heat. Add the onion and cook for 4 minutes, stirring frequently, until translucent and fragrant. Add the garlic and sauté for another 30 seconds. Return the cooked broccoli to the saucepan and stir to combine everything, then remove from the heat.

step 4 combine tuna and creme fraiche.

4. Combine tuna and crème fraiche

In a medium mixing bowl, combine the tuna and crème fraiche. Season with salt and pepper. I used 1 teaspoon of salt and 1/2 teaspoon of pepper, but please adjust according to your taste.

step 5 assemble casserole.

5. Assemble casserole

Place the broccoli, tuna mixture, and halved cherry tomatoes into the prepared casserole dish. Stir to combine. Sprinkle with the shredded cheddar cheese and top with the sliced mozzarella cheese.

step 6 bake casserole.

6. Bake

Bake the casserole uncovered for 15 minutes, until the sauce is bubbling and the cheese has melted and looks golden brown.

Broil: If you want the cheese topping to be browned more, broil the casserole for 2 to 3 minutes.

step 7 serve tuna broccoli casserole.

7. Serve

Take the tuna casserole out of the oven and let cool for 10 minutes. If desired, garnish with fresh basil leaves and a few cracks of black pepper. Serve warm and enjoy!

Serving suggestions: Broccoli tuna casserole makes a delicious and filling standalone meal. We also love it with garlic bread, alfredo pasta, or scalloped potatoes on the side.

Store & Reheat

  • Store: Let leftover tuna broccoli casserole cool completely. Then transfer it into an airtight container and keep in the fridge for 3 to 4 days. I don’t recommend freezing this casserole because the broccoli will become mushy and the sauce can split.
  • Reheat: To reheat, cover the casserole with foil and bake in the oven at 350°F / 180°C / gas mark 4 until hot and bubbly. Microwaving works, too, but the broccoli will be more mushy.
  • Meal prep: Cook the broccoli and assemble the casserole the day before. Cover your baking dish tightly with plastic wrap and place it in the fridge overnight. On the day of, let the casserole sit on the counter as the oven reheats, then bake for 20 minutes.

More easy seafood recipes

broccoli tuna casserole.

Tuna Broccoli Casserole Recipe

Yield: 6 servings
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 35 minutes

Craving a simple and delicious meal? Then this easy tuna broccoli casserole is for you! The recipe combines flaky tuna, tender broccoli, sweet cherry tomatoes, and melty cheese in a creamy dish that is ready in 35 minutes.

Ingredients

  • 1 bunch fresh broccoli (2 to 3 heads, cut into florets)
  • 1 large onion, chopped
  • 2 garlic cloves, finely minced
  • 2 tablespoons olive oil
  • 3 5-oz cans / 300 g tuna, drained
  • 7.5 oz / 210 g crème fraiche
  • 1 cup / 150 g / 5.3 oz cherry tomatoes, halved
  • 6 oz / 170 g mozzarella cheese, sliced
  • 1 cup / 120 g / 4 oz shredded sharp white cheddar cheese
  • 2 tsp salt, divided
  • 1/2 tsp black pepper
  • fresh basil leaves (to garnish, optional)

Instructions

  1. Prep work. Preheat your oven to 400°F / 200°C / gas mark 6. Spray a 9x13-inch / 23x33 cm baking dish with cooking spray. Set aside.
  2. Cook broccoli. Bring a large saucepan of water to a simmer. Add the broccoli and 1 teaspoon salt. Cook uncovered for 5 minutes, until crisp-tender. Drain and set aside.
  3. Sauté aromatics. In the same saucepan, heat the oil over medium heat. Add the onion and cook for 4 minutes, stirring frequently, until translucent and fragrant. Add the garlic and sauté for another 30 seconds. Return the cooked broccoli to the saucepan and stir to combine everything, then remove from the heat.
  4. Combine tuna and crème fraiche. In a medium mixing bowl, combine the tuna and crème fraiche. Season with salt and pepper. I used 1 teaspoon of salt and 1/2 teaspoon of pepper, but please adjust according to your taste.
  5. Assemble casserole. Place the broccoli, tuna mixture, and halved cherry tomatoes into the prepared casserole dish. Stir to combine. Sprinkle with the shredded cheddar cheese and top with the sliced mozzarella cheese.
  6. Bake. Bake the casserole uncovered for 15 minutes, until the sauce is bubbling and the cheese has melted and looks golden brown.
  7. Serve. Take the tuna casserole out of the oven and let cool for 10 minutes. If desired, garnish with fresh basil leaves and a few cracks of black pepper. Serve warm and enjoy!

Notes

Don’t cook the broccoli all the way: You want the broccoli just tender and slightly undercooked. The broccoli will continue to soften as you bake the casserole.

Drain well to avoid a watery casserole: I like to dump the cooked broccoli into a colander in the sink to drain while I sauté the onion and garlic. To save on dishes, sauté the aromatics in the same saucepan or pot you cooked the broccoli in.

Broil: If you want the cheese topping to be browned more, broil the casserole for 2 to 3 minutes.

Serving suggestions: Broccoli tuna casserole makes a delicious and filling standalone meal. We also love it with garlic bread, alfredo pasta, or scalloped potatoes on the side.

Nutrition Information:
Yield: 6 Serving Size: 1
Amount Per Serving: Calories: 423Total Fat: 33gSaturated Fat: 18gTrans Fat: 1gUnsaturated Fat: 13gCholesterol: 109mgSodium: 1162mgCarbohydrates: 6gFiber: 1gSugar: 3gProtein: 27g

As Seen On

brand logos
brand logos
brand logos
Skip to Recipe
// First try loading jQuery from Google's CDN // Fall back to a local copy of jQuery if the CDN fails