Diving into a low carb lifestyle doesn't mean giving up comfort food classics. This low carb tuna casserole delivers all the creamy, savory goodness you crave, without the heavy carbs. Packed with protein and healthy fats, it's a satisfying meal that fits perfectly into your health goals.

Why This Recipe Works

Uses cauliflower instead of pasta, slashing carbs while boosting fiber and vitamins.
Canned tuna provides lean protein and omega-3 fatty acids for heart health.
Rich, creamy sauce comes from a blend of cream cheese and cheddar, adding calcium and flavor.
Quick to prepare with simple, pantry-friendly ingredients.

Ingredients

1 medium head cauliflower, cut into small florets
2 cans (5 oz each) solid white tuna in water, drained and flaked
4 oz cream cheese, softened
1/2 cup heavy cream
1/2 cup chicken or vegetable broth
1 cup shredded sharp cheddar cheese, divided
1/4 cup grated Parmesan cheese
1/2 cup frozen peas
1/4 cup chopped yellow onion
2 cloves garlic, minced
2 tbsp butter
1/2 tsp salt
1/4 tsp black pepper
1/4 tsp paprika
2 tbsp chopped fresh parsley (optional, for garnish)

Equipment Needed

Large pot
Colander
Large skillet or sauté pan
Wooden spoon or spatula
9×9-inch baking dish (or similar 2-quart dish)
Mixing bowl
Measuring cups and spoons

Instructions

Prep the Cauliflower

Bring a large pot of salted water to a rolling boil. Add the cauliflower florets and cook for 5 to 6 minutes, until just tender but still firm.

You want them to hold their shape, not turn mushy. Drain well in a colander and set aside.

This par-cooking ensures the cauliflower finishes perfectly in the oven without becoming waterlogged.

Sauté the Aromatics

In a large skillet over medium heat, melt the 2 tablespoons of butter. Add the chopped onion and cook for about 3 minutes, stirring occasionally, until it becomes translucent and fragrant.

Add the minced garlic and cook for 30 seconds more until you can smell it. Be careful not to burn the garlic, as it will turn bitter.

Build the Cream Sauce

Reduce the heat to low and add the softened cream cheese to the skillet. Stir constantly until it melts into the butter and onions.

Slowly pour in the heavy cream and chicken broth while whisking to create a smooth, lump-free sauce. Let it simmer gently for 2 to 3 minutes, stirring, until it thickens slightly and coats the back of a spoon.

Combine the Casserole Base

Remove the skillet from the heat. Stir in 3/4 cup of the shredded cheddar, the Parmesan cheese, salt, pepper, and paprika until the cheeses are fully melted and the sauce is creamy.

Gently fold in the drained tuna, cooked cauliflower, and frozen peas. Make sure everything is evenly coated with the sauce.

Assemble and Bake

Preheat your oven to 375°F. Transfer the mixture to a lightly greased 9×9-inch baking dish and spread it into an even layer.

Sprinkle the remaining 1/4 cup of cheddar cheese over the top. Bake for 20 to 25 minutes, until the casserole is bubbling around the edges and the top is golden brown.

For an extra crispy top, broil for 1 to 2 minutes at the end. Watch carefully to prevent burning.

Tips and Tricks

Maximize Cauliflower Texture

After draining the cooked cauliflower, pat it dry with paper towels to remove excess moisture. This prevents a watery casserole and helps the sauce cling better, giving you a creamier final dish.

Boost the Flavor

Add a tablespoon of Dijon mustard or a splash of Worcestershire sauce to the cream sauce for an extra layer of savory depth. These umami boosters complement the tuna beautifully without adding carbs.

Perfect Reheating

Leftovers can be reheated in a 350°F oven for about 15 minutes, or until warmed through. The microwave works too, but the oven keeps the top crispy. If the casserole seems dry, add a splash of cream or broth before reheating.

Recipe Variations

Swap tuna for canned salmon or cooked shredded chicken for a different protein.
Add 1/2 cup sliced mushrooms sautéed with the onions for an earthy flavor.
Use broccoli florets instead of cauliflower for a different vegetable base.
Make it dairy-free by using dairy-free cream cheese, heavy cream substitute, and vegan cheddar shreds.

Frequently Asked Questions

How many carbs per serving?

This low carb tuna casserole contains approximately 8 grams of net carbs per serving, depending on the exact ingredients used. The cauliflower and peas contribute most of the carbs, but the portion is small enough to fit into a ketogenic or low carb diet.

Can I make this ahead of time?

Yes, you can assemble the casserole up to 24 hours in advance. Cover and refrigerate it unbaked.

When ready to eat, add about 10 minutes to the baking time since you'll be starting from a cold dish. Let it sit at room temperature for 20 minutes before baking for more even cooking.

Can I freeze this casserole?

Absolutely. Assemble the casserole but do not bake it.

Wrap the dish tightly with plastic wrap and then foil. Freeze for up to 3 months.

To serve, thaw in the refrigerator overnight, then bake as directed, adding 10 to 15 minutes to the baking time.

What can I use instead of cream cheese?

You can substitute 4 ounces of full-fat sour cream or Greek yogurt for the cream cheese. Keep in mind that Greek yogurt has a tangier flavor and may curdle if heated too quickly, so stir it in off the heat. For a dairy-free option, use a plain dairy-free cream cheese alternative.

Summary

This low carb tuna casserole proves you don’t need pasta to enjoy a hearty, creamy comfort meal. With cauliflower, a rich cheese sauce, and flaky tuna, it’s nutritious, satisfying, and easy to make. Perfect for busy weeknights or meal prep, it’s a keeper.