Creamy Keto Tuna Casserole Your New Favorite Dinner Delight

Last Updated on February 12, 2026 by Aniela Recipes Team

The first chill of autumn filled the air, and I found myself craving comfort food that didn t compromise my keto lifestyle. After rummaging through my pantry, I came across some albacore tuna and fresh veggies you d never guess I was about to create a dish that s both hearty and healthy! Enter my Keto Tuna Casserole, a delightful twist on the classic comfort food.

With layers of sautéed cabbage mingling with creamy Parmesan and zesty lemon, this casserole is an unexpected delight that will have your taste buds singing! Not only is it quick to prepare, but it also transforms easily into a family favorite. Whether you re a seasoned chef or just starting to explore homemade meals, there s something incredibly rewarding about watching the cheese turn golden brown under the broiler. So, let s dive into this cozy dish that promises to banish weeknight dinner boredom while keeping your health goals intact!

Why is Keto Tuna Casserole a Must-Try?

Comforting and Creamy: This dish brings warmth to your table, with a luscious sauce that wraps around every bite.

Quick and Easy: Perfect for busy weeknights, it comes together in a snap, making it an excellent choice for those hectic evenings.

Nutritious Twist: Loaded with veggies, it s a delicious way to sneak in your greens while adhering to a keto diet.

Crowd-Pleasing: Whether you re cooking for family or friends, this casserole is sure to impress, leaving everyone asking for seconds.

Versatile Flavor: The combination of dill and lemon elevates traditional tuna casserole, adding a refreshing zest. Don t forget to check out our family-friendly meal ideas for more delicious recipes!

Keto Tuna Casserole Ingredients

For the Casserole
Olive oil 2 tablespoons for sautéing the veggies and adding heart-healthy fats.
Butter 2 tablespoons to enhance the richness and flavor of the sauce.
Green cabbage 1 medium head, shredded; this low-carb alternative keeps it keto-friendly while offering a nice crunch.
Chopped onion 1 cup to provide savory depth to the dish.
Celery 3 ribs, chopped; adds a refreshing bite and a hint of sweetness.
Garlic 2 cloves, minced for fragrant aromatic goodness.
Sea salt and black pepper to taste; essential seasonings that elevate all flavors.
Dried dill or fresh dill 2 teaspoons dried or 2 tablespoons fresh; a pivotal herb that brightens the overall taste.
Dry mustard powder 2 teaspoons, lending a subtle tanginess to your casserole.
Lemon zest 1 tablespoon to add a burst of brightness.
Lemon juice from 1 lemon for a refreshing acidity that cuts through the creaminess.
Heavy cream 1 ½ cups; a rich base that brings the casserole s sauce together.
Grated Parmesan cheese 1 ¼ cups total, with 1 cup for the sauce and ¼ cup for topping; contributes creaminess and that golden, crispy layer.
Albacore tuna 3 cans (5 oz each), drained; packed with protein and is the star of our keto tuna casserole.
Frozen peas ½ cup for a pop of color and added nutrients.

Transform your weeknight dinners with this Keto Tuna Casserole that blends comfort and health in every bite!

How to Make Keto Tuna Casserole

1. Heat the olive oil and butter in an extra-large ovenproof skillet over medium heat. Let the oil shimmer, creating a lovely base for your veggies to sauté perfectly.

2. Sauté the cabbage, onion, celery, garlic, along with sea salt and black pepper. Cook until the vegetables are crisp-tender, about 10 minutes, ensuring they keep their bright color and crunch.

3. Mix in the dill, mustard powder, lemon zest, and lemon juice. Stir until the flavors meld together, creating a zesty aroma that fills your kitchen!

4. Pour in the heavy cream and add 1 cup of Parmesan cheese. Keep stirring until the cheese completely melts and blends into the creamy sauce, making it luscious and inviting.

5. Simmer by reducing the heat to medium-low, allowing the mixture to thicken slightly. Keep an eye on it; you want a velvety texture that clings to the ingredients.

6. Stir in the drained tuna and frozen peas. Gently fold them into the mixture, ensuring every bite will delight with flavor and nutrition.

7. Sprinkle the remaining ¼ cup of Parmesan over the top. This golden layer is essential it s what makes your casserole irresistible!

8. Broil on high for 3-5 minutes, watching closely until the cheese turns a beautiful golden brown crust. It s the crowning glory of your casserole!

Optional: Garnish with fresh dill before serving for an extra touch of brightness.

Exact quantities are listed in the recipe card below.

How to Store and Freeze Keto Tuna Casserole

Fridge: Store leftovers in an airtight container for up to 3 days. Reheat individual portions in the microwave or on the stovetop until warmed through.

Freezer: You can freeze the casserole for up to 2 months. Ensure it s in a freezer-safe container, and wrap it tightly to prevent freezer burn.

Thawing: When ready to enjoy, thaw overnight in the fridge. Reheat gently in the oven or microwave until piping hot.

Serving Tip: A fresh sprinkle of lemon juice and herbs after reheating brightens up the flavors, keeping your Keto Tuna Casserole delicious!

Keto Tuna Casserole Variations & Substitutions

Feel free to get creative with this dish, as it adapts beautifully to your taste preferences and dietary needs!

• Dairy-Free: Substitute heavy cream with coconut cream and use nutritional yeast instead of Parmesan for a creamy, cheese-like flavor.

• Low-FODMAP: Replace onion and garlic with the green tops of scallions to keep the delicious flavor without the FODMAPs.

• Texture Twist: Add crushed pork rinds on top before broiling for an unexpected crunch that gives this casserole a delightful contrast.

• Vegetable Boost: Incorporate other vegetables such as spinach, bell peppers, or zucchini to amp up the nutrition while adding vibrant colors.

• Spicy Kick: Stir in a teaspoon or two of crushed red pepper flakes or a splash of hot sauce for an exciting heat that will awaken your taste buds!

• Herb Infusion: Experiment with different herbs like thyme or basil instead of dill to give the casserole a unique aromatic spin.

• Protein Variation: Swap tuna for cooked chicken, shrimp, or even black beans for an entirely different protein experience.

• Nutty Flavor: For a distinctive twist, mix in some toasted pine nuts or slivered almonds to add a nice nutty depth to every bite.

What to Serve with Keto Tuna Casserole?

Picture a cozy family dinner where flavors come alive and loved ones gather around the table. These delightful pairings will elevate your meal experience!

• Crusty Bread: A warm, crusty loaf is perfect for soaking up that creamy sauce, creating a satisfying balance of textures.
• Garlic Green Beans: Tender green beans sautéed with garlic add a burst of freshness that complements the richness of the casserole beautifully.
• Simple Side Salad: A light salad with mixed greens, cherry tomatoes, and a tangy vinaigrette provides a refreshing contrast to the hearty casserole.
• Roasted Brussel Sprouts: Crisp-tender Roasted Brussel Sprouts tossed in a hint of balsamic glaze pair nicely, adding earthy flavors to your plate.
• Citrusy Quinoa: This fluffy, zesty quinoa dish enhances the meal with its bright notes, making each bite of casserole even more delightful.
• Lemonade Iced Tea: A refreshing glass of iced tea with a hint of lemon balances the richness of the casserole while keeping you cool and satisfied.
• Berry Crisp: End the meal on a sweet note with a warm berry crisp, as its natural sweetness and crunch play harmoniously after a savory main course.

With these enticing pairings, your Keto Tuna Casserole will shine even brighter and create the joyful dining experience you crave!

Expert Tips for Keto Tuna Casserole

Prep Your Veggies: Make sure all your vegetables are chopped and ready before you start cooking. This helps streamline your cooking process for the best Keto Tuna Casserole experience.

Check Consistency: When you simmer the sauce, it should be thick but not too thick. If it gets too thick, add a splash of cream or broth to loosen, ensuring every bite remains creamy.

Layering Cheese: For that golden crust, evenly sprinkle the Parmesan cheese just before broiling. This helps it melt uniformly and form a delightful crispy topping.

Tuna Variety: Opt for high-quality albacore tuna for a flavor boost. Avoid overcooking it during the mixing process to keep its tender texture intact.

Customize Flavor: Feel free to adjust the amount of dill and lemon based on your taste. A little extra dill can elevate the dish and make your Keto Tuna Casserole truly your own!

Make Ahead Options

These Keto Tuna Casserole ingredients are perfect for meal prep, making weeknight dinners a breeze! You can sauté the cabbage, onion, celery, and garlic up to 24 hours in advance; simply refrigerate the sautéed mixture in an airtight container. The creamy sauce (heavy cream and Parmesan) can also be prepared a day ahead just keep it separate until you re ready to bake. When it s time to cook, combine the prepped ingredients with the tuna and peas, then proceed with broiling as directed. This ensures your casserole remains just as delicious and mouthwatering while saving you precious time during busy weeknights.

Keto Tuna Casserole Recipe FAQs

How do I select the best cabbage for my Keto Tuna Casserole?
Choose a cabbage that feels heavy for its size with tightly packed leaves and no soft spots. Ideally, the outer leaves should be vibrant green without any dark spots or blemishes. This ensures the freshest and crispiest texture for your casserole!

Can I store leftover Keto Tuna Casserole?
Absolutely! Store leftovers in an airtight container in the fridge for up to 3 days. When reheating, I recommend using the microwave for individual portions or the stovetop for larger amounts, heating until warmed through and creamy.

Is it possible to freeze Keto Tuna Casserole?
Yes, you can freeze your casserole for up to 2 months! First, ensure it cools completely, then transfer it to a freezer-safe container, sealing it tightly to prevent freezer burn. When you re ready to enjoy it, just thaw overnight in the fridge, then reheat in the oven or microwave until it s piping hot.

What should I do if my sauce is too thick?
If your sauce thickens more than you d like, simply add a splash of cream or broth to loosen it. Stir it in gently over low heat until it reaches your desired creamy consistency. This step ensures that every bite of your Keto Tuna Casserole remains luscious and enjoyable.

Are there any dietary considerations I should be aware of for Keto Tuna Casserole?
If you or someone you re serving has allergies, be mindful of your ingredient choices. The casserole contains dairy; lactose-free cream and cheese can be great alternatives if lactose intolerant. Also, check the tuna label if there are concerns about preservatives or additives. Always confirm that the added ingredients fit your dietary preferences or needs!

What are some great ways to customize the flavor of my Keto Tuna Casserole?
The fun of cooking at home is experimenting with flavors! You can increase the amount of dill for a herbaceous kick or add a dash of hot sauce for some heat. Consider mixing in other vegetables like spinach or mushrooms for texture and more nutrients. The possibilities are endless, so enjoy making it your own!