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Cheesy Low-Carb Tuna Casserole

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Comfort food for my partner is anything hot and cheesy, while eating too much heavy, cheesy foods often leave me feeling heavy. This keto recipe is the perfect balance for us, with creamy cheesy sauce spooned through lots of vegetables and canned tuna.

I usually use broccoli and cauliflower but you could use whatever you have on hand, including any frozen vegetables. Likewise, I like tuna here, but you could swap out for another fish — either tinned, smoked, or cooked salmon, sardines or mackerel — all would work. If you're not a fan of fish, feel free to use cooked chicken or turkey.

This recipe will make 4 regular-small servings or 2-3 generous servings. Enjoy!

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Hands-on Overall

Nutritional values (per serving, about 255 g/ 9 oz)

Net carbs5.5 grams
Protein30.8 grams
Fat26.1 grams
Calories376 kcal

Calories from carbs 6%, protein 32%, fat 62%

Total carbs8.1 gramsFiber2.6 gramsSugars3.2 gramsSaturated fat15.8 gramsSodium548 mg(24% RDA)Magnesium52 mg(13% RDA)Potassium559 mg(28% EMR)

Ingredients (makes 4 servings)

  • 1/2 head broccoli (200 g/ 7.1 oz)
  • 1/2 head small cauliflower (200 g/ 7.1 oz)
  • 1 large can of tuna, drained (375 g/ 13.2 oz)
  • 1 recipe Keto Cheese Sauce (makes about 1 cup/ 240 ml)
  • 3/4 grated mozzarella cheese or cheddar (85 g/ 3 oz)


  1. Preheat oven to 180 °C/ 355 °F (conventional), or 160 °C/ 320 °F (fan assisted).
  2. Chop the broccoli and cauliflower into small florets and steam until just tender. Set aside to cool slightly. If you're using frozen and thawed vegetables, you won't have to cook them. Cheesy Low-Carb Tuna Casserole
  3. Add the vegetables and tuna to a large ovenproof dish and pour over the sauce, then gently stir through.
    Cheesy Low-Carb Tuna Casserole
  4. Sprinkle with the cheese.
    Cheesy Low-Carb Tuna Casserole
  5. Bake 15 minutes or until golden on top.
    Cheesy Low-Carb Tuna Casserole
  6. Serve or let it cool down and store in the fridge up to 5 days. Reheat before serving.
    Cheesy Low-Carb Tuna Casserole

Ingredient nutritional breakdown (per serving, about 255 g/ 9 oz)

Net carbsProteinFatCalories
Broccoli, fresh
2 g1.4 g0.2 g17 kcal
Cauliflower, fresh
1.5 g1 g0.1 g13 kcal
Tuna, tinned (in brine), drained
0 g18.2 g0.9 g81 kcal
Keto Cheese Sauce (KetoDiet blog)
0.8 g5.2 g20.7 g203 kcal
Mozzarella cheese (low moisture, for pizza)
1.2 g5 g4.2 g63 kcal
Total per serving, about 255 g/ 9 oz
5.5 g30.8 g26.1 g376 kcal
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Dearna Bond

Dearna is a passionate foodie and food photographer, and loves sharing her knowledge and enthusiasm for both via her food blog and online photography courses.

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Comments (2)

Hello. I really want to make this. My younger sister bought me a 600ml double cream for the cheese sauce. This recipe only calls for 60mls. What do I do with the remaining cream? Especially as the cream has a very short shelf life. Would the cream last longer if I freeze it?
I've been going through this app for quick recipes that use double cream and I found chocolate truffles. But there'll still be loads of cream left!!


Hello Amina, you can freeze cream in an ice tray or in a freezer-friendly container.
Or you could make keto coffee creamer and condensed milk: Low-Carb & Keto Coffee Creamer Five Ways, or ice cream:
Truffles are an option too 😊