As I rifled through my pantry one hectic evening, my eyes landed on a few cans of albacore tuna. A lightbulb moment struck: why not transform this forgotten staple into something delectable? Enter my Easy Keto Tuna Casserole with Creamy Parmesan Sauce. This dish is a low-carb and gluten-free triumph that captures the comforting essence of traditional casseroles without the guilt. Picture a warm blend of sautéed veggies, tender tuna, and a zesty parmesan topping bubbling to perfection, all while being an effortless weeknight meal. It’s not just quick and easy; this casserole is also a family favorite that pleases both keto enthusiasts and modern home chefs alike. Are you ready to relish in a classic dish updated for today’s lifestyle? Let’s dive in!

Why is this casserole a must-try?

Comforting and Familiar: This Keto Tuna Casserole mirrors the classic flavors you adore, making it a nostalgic favorite without the carbs.
Quick to Prepare: With only a handful of ingredients and easy steps, you can whip up this meal in no time—perfect for busy weeknights!
Versatile Options: Feel free to swap albacore tuna for shredded chicken or toss in other veggies like mushrooms for a personal touch.
Health-Conscious Delight: Gluten-free and low-carb, this dish lets you enjoy a hearty meal while sticking to your dietary goals.
Crowd-Pleasing Satisfaction: Gather your family around this creamy masterpiece; it’s bound to become a new household favorite. If you’re looking for more nutritious comfort dishes, try my delicious Potato Egg Casserole or fresh Avocado Tuna Salad!

Keto Tuna Casserole Ingredients

For the Base

Olive Oil – Used for sautéing vegetables; it offers a healthy fat source for your dish.
Butter – Adds richness and enhances flavor; can be substituted with additional olive oil for a dairy-free option.
Onion – Provides sweetness and aromatic depth; yellow or sweet onions work beautifully here.
Celery – Contributes texture and flavor; if you’re in a pinch, you can omit this ingredient.
Garlic – Infuses the dish with a strong aroma; fresh garlic is preferred, but garlic powder works too in a pinch.

For the Casserole

Sea Salt – Enhances overall flavor; always adjust according to your dietary needs.
Black Pepper – For seasoning; substitute with white pepper for a milder taste.
Cabbage – Serves as a low-carb noodle substitute; consider shredded zucchini or cauliflower for a change.
Dill – Adds an herbal note that brightens the dish; fresh dill wins, but dried will do in a pinch.
Mustard Powder – Provides a subtle tang; feel free to omit or swap for Dijon mustard if you like.
Lemon Zest & Juice – Brightness and acidity balance out the flavors; always use fresh lemons when possible.

For the Creamy Topping

Heavy Cream – Ensures a creamy texture; coconut cream or a non-dairy alternative can be used for a dairy-free version.
Parmesan Cheese – Adds cheesy richness; grated mozzarella or nutritional yeast are excellent alternatives.

For the Protein & Extras

Canned Albacore Tuna – The star of the dish; any canned tuna in water or oil works, but albacore is the least fishy.
Peas – Provide a pop of color and sweetness; feel free to swap them for other low-carb veggies like spinach or green beans.

Ready to dive into this delectable Keto Tuna Casserole? Gather these ingredients and let’s make mealtime a delightful affair!

Step‑by‑Step Instructions for Keto Tuna Casserole

Step 1: Heat the Base
In an extra-large ovenproof skillet, combine 2 tablespoons of olive oil and 1 tablespoon of butter over medium heat. Allow the butter to melt and the mixture to sizzle gently for about 1 minute. This will create a flavorful base for your Keto Tuna Casserole, so keep an eye on it while prepping the vegetables.

Step 2: Sauté the Vegetables
Add 1 cup of chopped cabbage, 1 diced onion, 1 cup of chopped celery, and 2 minced garlic cloves to the skillet. Sprinkle with 1 teaspoon of sea salt and ½ teaspoon of black pepper. Sauté these vegetables for 8 to 10 minutes, stirring occasionally, until they are crisp-tender and the onion is translucent. This step ensures a aromatic flavor infusion in your casserole.

Step 3: Mix in Seasonings
In a separate bowl, whisk together 2 teaspoons of fresh dill, 1 teaspoon of mustard powder, the zest of 1 lemon, and the juice from half of the lemon. Pour this mixture into the skillet over the sautéed vegetables, stirring well to combine. Cook for about 2 minutes, allowing the flavors to meld, turning your Keto Tuna Casserole into a zesty delight.

Step 4: Create the Creamy Sauce
Pour in 1 cup of heavy cream and 1 cup of grated Parmesan cheese into the skillet. Stir continuously for about 3 minutes until the cheese fully melts and integrates into a creamy sauce. Watch for the sauce’s rich texture to develop; it should begin bubbling gently, cascading a delicious aroma throughout your kitchen.

Step 5: Thicken the Sauce
Reduce the heat to medium-low and allow the sauce to simmer for about 5 minutes, stirring occasionally. This will help the sauce thicken nicely, making your Keto Tuna Casserole rich and satisfying. Be attentive to avoid burning the bottom, giving your dish a less-than-ideal taste.

Step 6: Add the Tuna and Peas
Gently fold in 2 cans of drained albacore tuna and 1 cup of frozen peas into the creamy sauce. Mix well to ensure the tuna is evenly distributed throughout the casserole. Allow this mixture to cook for another 2 to 3 minutes, letting those vibrant colors and flavors come together beautifully.

Step 7: Prepare for Baking
Preheat your broiler to high. Transfer the casserole mixture into the ovenproof skillet or a baking dish. For an extra cheesy touch, sprinkle the remaining ½ cup of Parmesan cheese evenly over the top. This will create a delicious, golden-brown layer once broiled.

Step 8: Broil to Perfection
Place the casserole under the broiler for 3 to 5 minutes, carefully monitoring it for browning. The cheese should bubble and take on a lovely golden hue. Remove the Keto Tuna Casserole from the oven once it’s beautifully crispy, letting it cool for a few minutes before serving.

Keto Tuna Casserole Variations

Feel free to get creative and make this Keto Tuna Casserole your own with these delightful twists!

Protein Swap: Substitute albacore tuna with shredded rotisserie chicken or salmon for a new flavor profile. Each option brings a unique taste and nutrition boost to your casserole.
Veggie Boost: Toss in additional vegetables like mushrooms or bell peppers for extra flavor and texture. Experimenting with seasonal veggies can truly elevate this dish!
Spicy Kick: For a touch of heat, mix in diced jalapeños or a dash of your favorite hot sauce. This quick addition transforms the casserole into a spicy delight that packs a punch!
Herb Variations: Swap dill for fresh thyme or oregano to create a completely different aromatic experience. These fresh herbs can bring an exciting new dimension to the flavor of your casserole.
Cheese Choices: Replace Parmesan cheese with grated mozzarella or nutritional yeast for a lighter, dairy-free option. Each of these alternatives will provide a different delightful flavor profile.
Nutty Crunch: Consider adding a sprinkle of toasted almond slivers or crushed pork rinds on top before broiling for added texture and flavor. They’ll provide a satisfying crunch to contrast the creaminess underneath.
Zucchini Noodles: Instead of cabbage, use spiralized zucchini for a fun twist. The zucchini gives a fresh taste while maintaining that low-carb goodness.
Chill and Serve: Serve this casserole cold as a creamy salad by omitting the baking step and tossing in some chopped fresh herbs and lemon juice. It’s a fantastic option for warm days!

Each variation can create a unique meal that reflects your personal taste. For additional inspiration, check out my comforting Potato Egg Casserole or fresh and vibrant Avocado Tuna Salad! Enjoy your culinary journey with every bite!

Make Ahead Options

This Keto Tuna Casserole is fantastic for meal prep, helping busy cooks save time while still delivering comfort food vibes! You can sauté the vegetables and prepare the creamy sauce up to 24 hours in advance. Simply store them in an airtight container in the refrigerator. When you’re ready to serve, combine the mixture with the tuna and peas, and bake as directed for the ultimate weeknight dinner. To maintain the quality, avoid pre-baking; this ensures your casserole remains just as delicious when finished. With these make-ahead options, you’ll enjoy all the flavors of this Keto Tuna Casserole with minimal effort on busy days!

How to Store and Freeze Keto Tuna Casserole

Fridge: Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheating this Keto Tuna Casserole is best done in the oven for ideal texture.

Freezer: You can freeze the casserole for up to 2 months. Portion into freezer-safe containers, allowing some space for expansion, and thaw overnight in the fridge before reheating.

Reheating: To reheat, place in the oven at 350°F (175°C) for about 20-25 minutes, or until heated through. Cover with foil to prevent browning if needed.

Avoid Overcooking: When reheating, keep an eye on it to ensure the creamy texture remains intact and doesn’t dry out.

Expert Tips for Keto Tuna Casserole

• Sautéing Skill: Ensure vegetables are sautéed just until crisp-tender to retain texture in your casserole. Overcooking can lead to a mushy result.

• Cheese Quality: Use a high-quality Parmesan cheese for the best flavor. It’s the key to that deliciously creamy topping everyone will love!

• Noodle Alternatives: If you decide to use low-carb noodles like zucchini or other substitutes, adjust the cooking time to avoid mushiness.

• Keep an Eye on Broiling: Broiling can vary in speed depending on your oven. Watch closely to prevent burning as you achieve that perfect golden-brown cheese crust.

• Save Time: Prepare your veggies ahead of time for those busy weeknights. This simple step can reduce prep time and keep your casserole easy and satisfying!

Enjoy whipping up your comforting Keto Tuna Casserole with these helpful tips!

What to Serve with Easy Keto Tuna Casserole

Picture a warm, inviting meal that brings together comfort and nutrition effortlessly, just waiting to be enjoyed with loved ones.

Simple Green Salad: Fresh greens and a light vinaigrette add a crisp contrast, balancing the richness of the casserole. Topping it with cucumbers or cherry tomatoes enhances the flavors, creating a delightful bite.
Garlic Butter Brussels Sprouts: Roasted to perfection, these tender sprouts complement the creamy casserole, providing a lovely crunch. Their earthy flavor pairs beautifully with the robust taste of the tuna.
Roasted Cauliflower: This low-carb vegetable is a fantastic side that absorbs flavors well; seasoning it with garlic and herbs gives a satisfying bite alongside your casserole.
Zucchini Noodles: These spiralized noodles bring another layer of freshness and texture, embracing the dish’s low-carb theme. Tossing them in olive oil and lemon juice makes them even more vibrant.
Cheesy Cauliflower Mash: A creamy, cheesy alternative to traditional mashed potatoes, this dish enhances your meal’s comfort factor while keeping it keto-friendly.
Crispy Air Fryer Asparagus: The crispiness of air-fried asparagus provides a fun texture that makes each bite interesting. Plus, its bright green color perfectly complements the casserole, creating an appealing plate.
Sparkling Water or Lemonade: A refreshing drink, sparkling water with a splash of lemon or a homemade lemonade is perfect to cleanse the palate, enhancing the comforting experience of your high-calorie meal.

These pairings offer a delightful variety of textures, flavors, and freshness that perfectly complement your Easy Keto Tuna Casserole, transforming dinner into a delightful feast!

Easy Keto Tuna Casserole Recipe FAQs

How do I choose ripe ingredients for my Keto Tuna Casserole?
Absolutely! When selecting your ingredients, pick vibrant, crisp cabbage without any dark spots or wilting. For onions, choose those that feel firm and have a smooth skin. Fresh garlic should be plump with no signs of sprouting, and herbs, like dill, should be bright green and fragrant.

How should I store leftover Keto Tuna Casserole?
Very good question! Store your leftovers in an airtight container in the fridge for up to 3 days. It’s best to reheat in the oven to maintain the creamy texture; simply cover with foil and pop it in at 350°F (175°C) for about 20-25 minutes.

Can I freeze my Keto Tuna Casserole? What’s the best method?
You can freeze this casserole for up to 2 months! First, allow it to cool completely. Then, transfer it to freezer-safe containers, leaving some space for expansion. To reheat, thaw it overnight in the fridge, then bake in the oven at 350°F (175°C) for about 20-25 minutes until hot throughout.

What should I do if the casserole turns out too watery?
If your casserole is too watery, it might mean the sautéed vegetables released extra moisture. To remedy this, you can simmer the mixture on low heat for a few extra minutes before pouring it into the baking dish to allow some of the moisture to evaporate. You can also add a bit more cheese or a keto-friendly thickener to help bind everything together.

Is this Keto Tuna Casserole safe for people with gluten allergies?
Absolutely! This Keto Tuna Casserole is naturally gluten-free since it uses cabbage instead of traditional pasta. However, if you use store-bought ingredients, always check labels for hidden gluten. Additionally, share any dietary restrictions with diners if you’re serving this casserole to guests.

Can I substitute the albacore tuna with other proteins?
Yes indeed! For a delightful twist, you can swap the albacore tuna for shredded rotisserie chicken or canned salmon. Each alternative brings its unique flavor profile, keeping the spirit of this easy dish while allowing for creative variation!