Introduction

If you’re on the hunt for a cozy, comforting meal that aligns perfectly with your low-carb lifestyle, this Keto Tuna Casserole with Cabbage and Parmesan is calling your name. First, thank you so much for stopping by—I absolutely love sharing recipes that bring both flavor and simplicity to your kitchen. This dish has quickly become a favorite in my home, and I’m thrilled to pass it on to you!

Filled with creamy textures, savory tuna, tender cabbage, and that irresistible Parmesan crust, this keto casserole is hearty enough for dinner and easy enough for any weeknight. The combination of cabbage and cheese gives this keto tuna casserole a delightful twist—you won’t miss the pasta one bit.

👉 Don’t want to lose this recipe? Make sure to subscribe to get it delivered straight to your inbox! I share exclusive tips and bonus recipes only with my email friends. Let’s get cozy and cook something delicious!

Why You’ll Fall in Love with This Keto Tuna Casserole

There’s a reason why casseroles never go out of style—they’re the culinary equivalent of a hug. This one is:

Low-carb and keto-friendly: At under 6g net carbs per serving, this casserole fits easily into your macros.
Budget-friendly: Tuna and cabbage are both affordable staples.
Family-approved: Creamy, cheesy, and satisfying, even non-keto eaters will dig in.
Make-ahead friendly: Perfect for meal prep, this casserole keeps well and reheats beautifully.

What Does This Keto Casserole Taste Like?

Imagine a creamy tuna melt… baked into a golden casserole dish with tender cabbage instead of bread. The cabbage takes on a silky texture once baked, and the Parmesan on top creates a savory, crispy crust that’s anything but boring!! The tuna adds a salty richness, and the cream and cheese make it extra indulgent—without any of the carbs you’re avoiding.

Benefits of Making Keto Tuna Casserole with Cabbage

High in protein and healthy fats
Great source of Omega-3s from tuna
Cabbage is full of fiber, Vitamin C, and antioxidants
No processed ingredients or weird fillers
One-pan meal = easy clean-up 🙌

Ingredients

Here’s what you’ll need for this flavorful casserole:

2 tablespoons butter
1 small onion, finely chopped
2 cloves garlic, minced
1 small head green cabbage, thinly sliced (about 5 cups)
2 (5 oz) cans tuna in olive oil, drained
¾ cup sour cream
½ cup heavy cream
1 teaspoon Dijon mustard
1½ cups shredded mozzarella cheese
¾ cup grated Parmesan cheese
1 teaspoon dried thyme
Salt and pepper to taste
Optional: crushed red pepper flakes for heat

Kitchen Tools You’ll Need

Large skillet or sauté pan
9×13” casserole dish
Mixing bowl
Sharp knife or mandoline for slicing cabbage
Cheese grater (if grating fresh Parmesan)

Ingredient Substitutions & Additions

I promised you versatile, and here’s proof! This casserole is super customizable:

No sour cream? Use Greek yogurt or cream cheese (softened).
Different fish? Swap tuna with canned salmon or shredded rotisserie chicken.
More veggies? Add sautéed mushrooms or spinach.
Extra cheesy? Stir in a little Gruyère or cheddar for added richness.
Spice it up: A few dashes of hot sauce or a sprinkle of cayenne do wonders!

How to Make Keto Tuna Casserole with Cabbage and Parmesan

Let’s break it down—this comes together in under 45 minutes!

Preheat your oven to 375°F (190°C).
Sauté the veggies: Melt butter in a large skillet over medium heat. Add onion and garlic, cooking until fragrant (about 2–3 minutes). Stir in the cabbage and cook until softened, about 8–10 minutes. Season with salt, pepper, and thyme.
Combine the filling: In a large bowl, mix together the cooked cabbage mixture, tuna, sour cream, heavy cream, Dijon mustard, and mozzarella. Adjust seasoning as needed.
Assemble the casserole: Spread the mixture into a greased 9×13″ baking dish. Sprinkle Parmesan over the top.
Bake it: Place the dish in the oven and bake for 20–25 minutes, or until bubbly and golden on top.
Optional broil: For extra crunch, broil for 2–3 minutes at the end—watch closely!

The smell when this is in the oven is incredible!! Warm, cheesy, and savory in all the right ways.

What to Serve with Keto Tuna Casserole

This casserole is rich and filling on its own, but here are a few low-carb pairing ideas:

A crisp green salad with lemon vinaigrette
Roasted asparagus or green beans
Keto garlic bread or almond flour biscuits
Pickled vegetables for a tangy contrast

Tips for the Best Keto Tuna Casserole

Don’t overcook the cabbage. You want it soft but still holding its shape.
Drain your tuna well. Excess liquid can make the casserole watery.
Use freshly grated Parmesan. It melts and browns better than the pre-packaged kind.
Let it rest. Wait 5–10 minutes before serving so it firms up—makes slicing easier!

How to Store and Reheat

This dish is fantastic for leftovers!

To store: Keep in an airtight container in the fridge for up to 4 days.
To freeze: Portion into freezer-safe containers and store for up to 2 months.
To reheat: Microwave individual portions, or warm in the oven at 350°F until heated through.

Frequently Asked Questions

Can I use bagged coleslaw mix instead of fresh cabbage?
Yes! It’s a great shortcut. Just make sure it’s plain (no added sauces).
Can I make this casserole dairy-free?
It would require a few changes—swap sour cream and heavy cream for coconut cream or a dairy-free alternative, and use nutritional yeast in place of cheese.
Is canned tuna really keto-friendly?
Absolutely! It’s high in protein and contains zero carbs—perfect for keto.
Can I make this ahead of time?
Totally. Assemble everything and refrigerate, then just pop it in the oven when you’re ready to bake.

In Conclusion

This Keto Tuna Casserole with Cabbage and Parmesan is the kind of recipe you’ll turn to again and again. It’s simple, satisfying, and bursting with comforting flavors—all while staying true to your low-carb goals. Whether you’re meal prepping or feeding the family, this dish is a keeper.