Tuna casserole is one of those nostalgic, comfort-food classics that never truly goes out of style. Whether you remember it from childhood dinners or you’re discovering it for the first time, the combo of creamy sauce, tender tuna, and bubbly cheese is hard to beat. This Keto Tuna Casserole takes everything you love about the traditional version and gives it a low-carb makeover—no noodles, no canned soup, no unnecessary fillers. Just real ingredients, creamy texture, and flavor that satisfies without spiking your carbs.
It’s the perfect meal when you want cozy without the crash, indulgence without the guilt, and a dinner that comes together with pantry staples. Plus, it’s gluten-free, low in carbs, high in protein, and perfect for make-ahead meals.
What Makes This Tuna Casserole Keto?
Classic tuna casserole usually includes:
- Pasta (often egg noodles or macaroni)
- A can of condensed cream soup
- Breadcrumb topping
All of which are not low-carb. This keto version swaps those ingredients for whole, keto-friendly substitutes while keeping the creamy texture and satisfying richness:
- Cauliflower replaces the noodles
- Heavy cream, cream cheese, and cheddar create a luxurious homemade sauce
- Almond flour or pork rind crumbs give the topping a golden crunch
The result? All the creamy, cheesy, savory comfort you expect—without the carbs.
Tuna: Picking the Right Kind for Keto Casserole
When tuna is the star of the show, choose one with good texture and flavor. Here’s what to look for:
- Solid white albacore tuna in water: Clean, mild flavor and flaky texture
- Tuna in oil: Richer and more filling—just drain well
- Sustainably caught or wild tuna: For better taste and quality
Avoid tuna that’s mushy or overly shredded, as it won’t hold up as well in the casserole.
Tip: Always drain tuna thoroughly before mixing it in to avoid watery casserole.
Cauliflower: The Low-Carb Pasta Stand-In
Cauliflower is the perfect keto replacement for noodles here—it’s neutral in flavor and takes on the creamy sauce beautifully.
Here’s how to prep it:
- Use fresh cauliflower florets for best texture
- Steam or microwave until just fork-tender—not mushy
- Pat dry with a clean towel to remove excess moisture
You can also use frozen cauliflower (thawed and drained well), or pre-riced cauliflower for a different texture, though whole florets give more bite and structure.
Building the Sauce: Rich, Creamy, and Keto-Perfect
This sauce is everything. It’s thick, savory, and cheesy, made from real ingredients that keep it keto-compliant:
- Heavy cream and cream cheese for richness
- Shredded cheddar for bold flavor
- Garlic, onion powder, and mustard to build depth
- Egg yolk for thickening and a silkier texture (optional but recommended)
This combination creates a smooth, velvety sauce that brings the whole casserole together.
Crunchy Topping (Without the Carbs)
You don’t need breadcrumbs to get that golden, baked finish. Here are keto-friendly topping ideas:
- Crushed pork rinds (classic, salty, and crunchy)
- Toasted almond flour or crushed slivered almonds
- Shredded Parmesan cheese, browned to a crispy finish
- Crushed sunflower seeds or pepitas (great for nut-free diets)
Add just a tablespoon of melted butter or olive oil to help the topping brown beautifully.
Ingredients
For the Casserole
- 1 large head cauliflower, cut into small florets (about 5–6 cups)
- 2 (5-ounce) cans tuna in water or oil, well drained
- 1 cup shredded sharp cheddar cheese
- ½ small onion, finely chopped (optional)
- 2 tablespoons chopped parsley or chives (for freshness)
For the Sauce
- ¾ cup heavy cream
- 4 ounces cream cheese, softened
- 1 egg yolk (optional, for thickening)
- ½ teaspoon garlic powder
- ½ teaspoon onion powder
- 1 teaspoon Dijon mustard
- Salt and pepper, to taste
For the Topping
- ¼ cup crushed pork rinds or almond flour
- 2 tablespoons shredded Parmesan cheese
- 1 tablespoon butter or olive oil
Instructions
- Prep the Cauliflower
Steam cauliflower florets until just fork-tender (about 5–7 minutes). Drain and pat dry with paper towels. Set aside. - Make the Sauce
In a saucepan over medium-low heat, combine heavy cream and cream cheese. Stir until smooth. Add garlic powder, onion powder, Dijon mustard, and salt/pepper. If using, whisk in the egg yolk and stir for 1–2 minutes until thickened. - Assemble the Casserole
Preheat oven to 375°F (190°C). In a large mixing bowl, combine steamed cauliflower, drained tuna, chopped onion (if using), parsley, and ¾ cup of the cheddar cheese. Pour in the sauce and mix gently to combine. - Transfer and Top
Pour mixture into a greased 9×9-inch (or similar size) baking dish. Sprinkle remaining ¼ cup cheddar over the top. - Make the Topping
In a small bowl, combine crushed pork rinds or almond flour, Parmesan, and melted butter. Sprinkle evenly over the casserole. - Bake
Bake uncovered for 20–25 minutes, until bubbly and lightly golden on top. Broil for 2–3 minutes at the end for extra crispness if desired. - Cool and Serve
Let rest for 5 minutes before serving. Garnish with fresh herbs or a sprinkle of cracked black pepper.
Storage and Reheating
- Fridge: Store in an airtight container for up to 4 days.
- Freezer: Freeze individual portions in airtight containers for up to 2 months. Thaw in the fridge overnight.
- Reheat: Warm in the microwave or oven at 325°F until heated through. Add a splash of cream if it looks dry.
What to Serve With Keto Tuna Casserole
While this casserole is filling on its own, you can pair it with:
- Keto garlic bread or cloud bread
- Simple green salad with lemon vinaigrette
- Roasted or sautéed greens (like spinach or kale)
- Zoodles or shirataki noodles for extra bulk
Variations and Add-Ins
Want to switch things up? Try these:
- Spicy tuna casserole: Add chopped jalapeños or a dash of cayenne
- Mushroom version: Sauté mushrooms with onions before mixing
- Extra cheesy: Add Monterey Jack or mozzarella for a milder melt
- Add eggs: Mix in two beaten eggs to firm up the bake into a sliceable, quiche-like texture
Nutrition Highlights (Per Serving Estimate)
- Calories: 320–350
- Protein: 25g
- Fat: 24g
- Net Carbs: 5–6g
(Note: Varies slightly based on topping and cauliflower size)
Comparisons and Similar Recipes
- Versus Classic Tuna Casserole: This one skips the noodles and soup for a fresher, low-carb take.
- Versus Tuna Melt: You get that same creamy tuna-cheese flavor without the bread.
- Versus Zoodle Tuna Bake: This version has more structure and classic feel thanks to the cauliflower.
Keto Tuna Casserole proves that comfort food and clean eating can absolutely go hand in hand. It’s creamy, craveable, and completely satisfying—with zero pasta and zero guilt. Whether you’re following a keto lifestyle or just looking for a low-carb dinner that actually tastes good, this casserole will earn its spot in your regular rotation.