Keto Tuna Casserole

Keto tuna casserole is the kind of warm, cheesy comfort food that never goes out of style—and now it fits right into your low-carb lifestyle. If you’ve been craving something hearty yet keto-friendly, this dish is just the thing. Rich tuna, gooey cheese, tender cauliflower, and a creamy sauce come together in one bubbling bake that feels like home in every bite.

This Keto tuna casserole draws on the tradition of classic American tuna noodle bakes but skips the carbs without sacrificing the flavor. Instead of pasta, you’ll get soft cauliflower florets that soak up all the savory goodness. The creamy base is made with full-fat dairy and real mayo—both keto staples—while a touch of garlic and onion adds depth.

What makes this version special is how effortlessly it all comes together. It’s quick enough for a weeknight, but comforting enough for a Sunday dinner. And it’s flexible too—you can spice it up, switch the cheese, or even add some green veggies for color.

The full printable Keto tuna casserole recipe is just below, but there are a few time-saving tips and flavor-boosting tricks up ahead that are worth your time. Whether you’re new to keto or a seasoned pro, this is one casserole you’ll want to keep on repeat.

Keto Tuna Casserole Ingredients

Making a delicious keto tuna casserole starts with choosing ingredients that deliver on flavor while keeping carbs in check. Every component in this dish has a role to play—bringing richness, structure, or just a little nostalgic comfort.

Here’s what you’ll need and how you can tweak it if needed:

• Canned Tuna – Choose a high-quality tuna packed in water or olive oil. It’s the star protein here and fully keto-approved. You can also use canned salmon or shredded chicken for variety.
• Cauliflower Florets – This is our low-carb stand-in for pasta. Steam or lightly roast them before mixing in so they don’t water down the casserole. Broccoli can also be used, but cauliflower gives that classic texture.
• Mayonnaise – Adds creaminess and binds everything together. Choose a full-fat, sugar-free version. Avocado oil-based mayo is a good clean alternative.
• Sour Cream or Cream Cheese – Either one works to enrich the sauce. Cream cheese makes it denser; sour cream adds a tangy bite. You can even do half-and-half for balance.
• Cheddar Cheese – Sharp cheddar brings bold, cheesy flavor. For extra meltiness, add a little mozzarella or Monterey Jack. Use pre-shredded sparingly—it often has added starch.
• Heavy Cream – Essential for a thick, keto-friendly sauce. If you prefer, use unsweetened almond milk with a bit of xanthan gum, but the richness of cream is hard to beat.
• Onion and Garlic Powder – These pantry staples keep things flavorful without carbs. A little goes a long way here.
• Grated Parmesan (optional topping) – For a golden crust on top, a sprinkle of parmesan gives great texture and flavor.

Optional Add-ins:

• Chopped spinach or kale for greens.
• Diced green chiles or jalapeños for a kick.
• Mushrooms for umami depth.

How to Make Keto Tuna Casserole (Step-by-Step Guide)

Making this keto tuna casserole is easy if you follow these steps! From prepping the cauliflower to layering in that creamy sauce, each part comes together in under an hour. The result? A cheesy, golden bake that satisfies without the carbs.

Step 1 – Prep the Cauliflower

Start by cutting a medium head of cauliflower into small, bite-sized florets. Steam or microwave them for 4–5 minutes until just tender. You want them soft but not mushy—they’ll finish cooking in the oven.

Step 2 – Mix the Creamy Base

In a large mixing bowl, combine ½ cup mayonnaise, ½ cup sour cream or cream cheese, ¼ cup heavy cream, 1 teaspoon each of onion and garlic powder, and a pinch of salt and pepper. Stir until smooth and creamy.

Step 3 – Add the Tuna and Cauliflower

Drain two cans of tuna well and flake it into the bowl. Gently fold in the cooked cauliflower along with 1½ cups shredded cheddar cheese. Make sure everything is well coated but don’t overmix.

Step 4 – Transfer to Baking Dish

Grease a medium-sized casserole dish and spread the mixture evenly. Top with extra shredded cheese and a sprinkle of grated parmesan if using. This helps create that crave-worthy golden crust.

Step 5 – Bake Until Bubbly and Golden

Place in a preheated 375°F oven and bake for 25–30 minutes, or until hot, bubbly, and lightly browned on top. Let it cool 5–10 minutes before serving for best texture.

Step 6 – Serving the keto tuna casserole

To serve the keto tuna casserole, portion it into individual servings using a spatula or serving spoon. Garnish with fresh parsley or chives for a pop of color and flavor. Pair it with a side salad or steamed vegetables for a balanced meal. Enjoy your delicious and satisfying low-carb dish.

Tips for Success

To make your keto tuna casserole turn out just right every time, a few thoughtful tips go a long way. From texture to flavor, these little details can help elevate the dish to comfort food perfection.

• Drain the tuna well – Excess liquid can make your casserole watery. Press the tuna gently with a fork in a strainer to remove as much moisture as possible.
• Avoid overcooking the cauliflower – It should be tender-crisp when it goes into the oven. Too soft, and it may turn mushy after baking.
• Use full-fat ingredients – Mayo, sour cream, and cheese should all be the real deal for flavor and richness. Low-fat products can change the consistency and aren’t as keto-friendly.
• Add cheese in layers – Mixing some into the filling and saving a handful for the top ensures gooey bites and a crispy, browned topping.
• Let it rest before serving – After baking, give it a few minutes to settle. This helps the sauce thicken up and keeps slices from falling apart on the plate.

Pro Tip: If you like a little crunch, top your keto tuna casserole with crushed pork rinds before baking for a keto “breadcrumb” topping that adds a savory finish.

Serving Suggestions

This keto tuna casserole is filling on its own, but it pairs beautifully with a few low-carb sides for a well-rounded meal. Whether you’re hosting a cozy dinner or prepping lunches, here are some easy ways to enjoy it.

• Serve with a crisp green salad – A simple salad with lemon vinaigrette adds brightness to balance the creamy casserole.
• Try it alongside roasted veggies – Zucchini, green beans, or asparagus roast up quickly and keep things keto-friendly.
• Add a comforting soup – A small bowl of roasted red pepper gouda soup makes a great starter or companion to this dish.

If you’re packing it for lunch, include a few olives or sliced avocado for healthy fats and flavor. This keto tuna casserole also reheats beautifully, so it’s perfect for meal prepping.

Variations and Customizations

One of the best things about keto tuna casserole is how easily you can adapt it to suit your taste—or what’s in your pantry. Whether you’re craving a different protein or looking for a dairy-free spin, there are plenty of ways to make it your own.

• Swap the Tuna: Not everyone’s a tuna fan. Try canned salmon for a richer flavor or shredded rotisserie chicken for a heartier take.
• Add Veggies: Stir in chopped spinach, mushrooms, or even chopped jalapeños for a spicy twist. Just be sure to sauté or steam them first to avoid excess moisture.
• Go Spicy: Mix in a spoonful of Dijon mustard or a dash of hot sauce into the creamy base. Crushed red pepper flakes on top also bring a nice kick.
• Make it extra cheesy: Add a mix of cheeses like mozzarella, gouda, or Monterey Jack. Smoked gouda in particular gives a lovely depth.
• Low-dairy version: Swap out sour cream for unsweetened coconut cream and use dairy-free cheese alternatives that melt well. Keep the texture creamy without relying fully on cheese.

This casserole is forgiving, so don’t be afraid to experiment. You’ll find that even small changes can create a totally new experience while keeping it keto.

How to Store and Reheat

Storing and reheating your keto tuna casserole is simple, and it tastes just as satisfying the next day—maybe even better. With the right storage methods, you can enjoy leftovers all week without losing that creamy, comforting texture.

• To Store: Let the casserole cool completely, then transfer to an airtight container. It will keep well in the refrigerator for 3 to 4 days.
• To Reheat: Warm individual portions in the microwave for 1–2 minutes, or reheat the full casserole in a 350°F oven for about 15 minutes. If reheating in the oven, cover with foil to prevent the top from over-browning.
• Tip: Add a splash of cream or a sprinkle of cheese before reheating to refresh the creaminess and flavor.

This dish is excellent for meal prep. Divide it into single-serve containers for quick lunches or dinners during a busy week.

Can You Freeze Keto Tuna Casserole?

Yes, you can freeze keto tuna casserole—and it holds up surprisingly well. This makes it a great option for planning ahead or saving leftovers for another week.

To freeze, let the casserole cool completely, then portion it into freezer-safe containers. If you plan to freeze the entire dish, wrap it tightly with plastic wrap and then foil. Label with the date and store for up to 2 months.

When ready to enjoy, thaw it overnight in the refrigerator. Reheat in a 350°F oven, covered with foil, until warmed through—usually about 25 minutes. If it looks dry, stir in a tablespoon of cream or add extra cheese before baking.

Freezing Tip: If you’re making it ahead, consider undercooking the cauliflower slightly. This helps it keep its texture after reheating.

FAQs About Keto Tuna Casserole

Curious about how this dish fits into your keto lifestyle? Here are some of the most common questions folks ask about keto tuna casserole—and what you need to know to enjoy it confidently.

Keto Tuna Casserole Recipe Card

Keto Tuna Casserole

Recipe by RebeccaCourse: DinnerCuisine: AmericanDifficulty: Easy

Servings

6

servings

Prep time

10

minutes

Cooking time

30

minutes

Calories

375

kcal

A creamy, cheesy low-carb tuna casserole perfect for keto dinners.

Gather Your Goodies

• 1 medium head cauliflower, cut into florets

• 2 cans (5 oz each) tuna in water or oil, drained

• ½ cup mayonnaise (sugar-free)

• ½ cup sour cream or 4 oz cream cheese

• ¼ cup heavy cream

• 1½ cups shredded sharp cheddar cheese

• 1 tsp onion powder

• 1 tsp garlic powder

• Salt and black pepper to taste

• Optional: ¼ cup grated parmesan cheese (for topping)

Let’s Get Cooking

• Preheat oven to 375°F (190°C). Lightly grease a medium casserole dish.
• Steam or microwave cauliflower until tender-crisp, about 4–5 minutes. Drain and let cool slightly.
• In a large bowl, whisk together mayonnaise, sour cream or cream cheese, heavy cream, garlic powder, onion powder, salt, and pepper.
• Fold in the tuna, cauliflower, and shredded cheddar. Mix gently to coat.
• Transfer mixture to casserole dish. Top with remaining cheese and optional parmesan.
• Bake for 25–30 minutes, until hot and bubbly with golden top. Let rest for 5–10 minutes before serving.

Notes

• Swap tuna with canned salmon or shredded chicken for variety. Add mushrooms, spinach, or jalapeños for extra flavor. Store leftovers in an airtight container in the fridge up to 4 days.

For more comforting recipe ideas and kitchen inspiration, follow us on TastyDo.

Final Thoughts on Keto Tuna Casserole

There’s something undeniably cozy about a warm, bubbling casserole—and this keto tuna casserole brings all that comfort without the carbs. It’s creamy, savory, and just cheesy enough to feel indulgent, all while staying true to a low-carb lifestyle.

Whether you’re meal prepping for the week or feeding the whole family on a busy night, this dish checks all the boxes. It’s easy to make, flexible enough to suit your taste, and stores beautifully. And let’s be honest—it’s the kind of old-school meal that never really goes out of style.

If you give it a try, I’d love to hear what you think. Leave a comment or a rating—and don’t be afraid to make it your own with your favorite add-ins or toppings.

And if you’re in the mood for another comforting bake, you might enjoy this classic chicken and dumpling casserole. It’s another hearty favorite that fits right into any cozy dinner rotation.