This keto tuna casserole is a true winner, it is easy, delicious, and nutritious! Picture this: tender chunks of canned tuna, vibrant florets of broccoli, and a luscious, creamy cheese sauce coming together into a bubbling, cheesy goodness! If you are on the lookout for a scrumptious low-carb dish, this hearty casserole is sure to satisfy. Get ready to savor the creamy decadence and wholesome goodness that await in every comforting bite!
Why we love this recipe!
- Budget friendly dinner using canned tuna and other basic ingredients.
- Only simple steps are required with no special equipment needed.
- Versatile – swap the tuna for shredded chicken, or change the veggies.
- The deliciously creamy, cheesy sauce makes it very family friendly.
What you will need to make this recipe
We love using canned tuna in our weeknight dinners because it is packed with protein, budget-friendly, and delicious! You only need basic grocery-store ingredients to make this keto tuna casserole, which you may already have in the fridge or pantry.
- Heavy whipping cream – Heavy whipping cream works best in this recipe. In Australia, we use pure cream or thickened cream.
- Cream cheese – We use block-style full-fat cream cheese in this recipe.
- Butter – Salted butter works fine in this recipe.
- Parmesan cheese – We like to use finely grated parmesan cheese in this recipe the cheese sauce is creamy. It adds loads of flavor too!
- Garlic powder – For convenience, we like to use garlic powder in this recipe, but fresh minced garlic would also work for a stronger garlic flavor.
- Cayenne pepper – This is optional, but it does add a nice subtle flavor to the cheese sauce.
- Salt and pepper
- Canned tuna – We prefer to use canned tuna in springwater in this recipe. Make sure it is well drained and then broken up into flakes.
- Broccoli – Fresh or frozen broccoli florets both work in this recipe.
- Shredded cheese – We like to use shredded cheddar cheese in this recipe, but you can use your preferred cheese. Colby, mozzarella, or shredded cheese blends would work well.
Equipment
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You may need,
Step by Step Instructions
This recipe is so delicious as it uses the best cheese sauce recipe on the internet! This cheese sauce recipe is simple to make and is the key to the flavor and creaminess of this keto tuna mornay recipe. Once you have the cheese sauce made and steamed the broccoli, it is as simple as putting it all in a baking dish and topping it with cheese, and baking it in the oven.
- Prepare the ingredients for the cheese sauce.
- Place all ingredients in a saucepan and whisk together until smooth. Simmer to allow it to thicken slightly.
- Steam the broccoli florets
- Start assembling the tuna casserole by placing the steamed broccoli in the bottom of a casserole dish in an even layer.
- Drain the tuna and then flake it in an even layer over the broccoli.
- Pour the cheese sauce over the broccoli and tuna, trying to cover the top later completely.
- Sprinkle the shredded cheese evenly over the top of the cheese sauce. Baking in the oven until golden brown and bubbling.
- Remove from the oven and allow to rest for 5 minutes before serving.
Delicious low carb tuna recipes
We love tuna and it is a fantastic source of protein on a low carb lifestyle. Canned tuna is also readily available in most grocery stores and budget friendly. It is quick and easy to make for packed lunches and perfect for use in meal prep.
Here are some of our other favourite low carb tuna recipes;
- Keto tuna salad lettuce cups
- Tuna salad without mayo
- Keto tuna patties
- Mexican tuna salad
- Keto tuna poke bowl
Expert tips, suggestions & how to store
- Keto chicken casserole – If you are not a fan of tuna or have some leftover shredded chicken, this recipe also works really well with shredded chicken in place of the tuna.
- Broccoli alternatives – You can substitute other cooked veggies in place of the broccoli. We like a combination of steamed broccoli and cauliflower.
- Make ahead – If you like to meal prep you can make the cheese sauce and steam the broccoli ahead of time and then assemble the casserole prior to cooking.
- Storage – The cooked keto tuna casserole will keep in the fridge for 4-5 days. We like to store it in Pyrex storage containers. It reheats well in the microwave or covered in the oven.
- Serving suggestions – As this meal contains a lot of protein and veggies we find it is a complete meal. You can also serve it with additional veggies or a side salad if you prefer.
FAQ’s
Canned tuna is perfect for a keto diet as it is packed with protein and has no carbohydrates. We prefer canned tuna in springwater or plain olive oil without any flavorings, we can then add our own preferred flavors.
Canned tuna that is unflavored and packed in springwater or olive oil has zero carbohydrates, so is keto-friendly. Fresh tuna also has zero carbs.
A traditional homemade tuna casserole usually contains pasta or rice and is at least 25g of carbohydrates per serve depending on the recipe and serving size. This keto tuna casserole only has 9g of total carbohydrates for a whole meal.
No, tuna by itself has very low to zero carbohydrates.
If you like this recipe you may also like…
- Teriyaki Chicken Rice Bowl
- Mexican Chicken Salad
- Mexican tuna salad
- Tuna Salad without Mayo
- Panko Chicken
- Cream Cheese Pasta
- Lemon Chicken Marinade
- Mexican chicken marinade
- Smoked Chicken Salad
- Tandoori Chicken Salad
Ingredients
Keto Cheese Sauce
- 1 cup heavy whipping cream
- 4 oz cream cheese, cubed (115g)
- 1 oz butter, cubed (30g)
- ¼ cup parmesan cheese, finely grated
- ½ tsp garlic powder
- 1-2 pinches cayenne pepper
- salt & pepper
Tuna Casserole Assembly
- 12 oz broccoli florets (350g)
- 4 cans tuna, drained (4 x 5oz cans) (450g)
- 4 oz cheddar cheese, shredded (115g)
Instructions
Keto Cheese Sauce
- Add all ingredients to a small saucepan and heat over medium.
- Whisk to combine and let simmer for a few minutes to combine and thicken slightly.
- Season with salt and pepper to taste.
Tuna Casserole Assembly
- Preheat oven to 350F/180C.
- Steam broccoli florets until just tender, don't overcook as they will cook a little more in the oven.
- Arrange broccoli in an oven-proof dish, sprinkle over tuna evenly. Pour over the prepared cheese sauce and sprinkle with grated cheese.
- Bake for 15-20 mins until golden on top and bubbling. Allow to cool for 5 mins before serving.
Video
Notes
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- Keto chicken casserole – If you are not a fan of tuna or have some leftover shredded chicken, this recipe also works really well with shredded chicken in place of the tuna.
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- Broccoli alternatives – You can substitute other cooked veggies in place of the broccoli. We like a combination of steamed broccoli and cauliflower.
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- Make ahead – If you like to meal prep you can make the cheese sauce and steam the broccoli ahead of time and then assemble the casserole prior to cooking.
-
- Storage – The cooked keto tuna casserole will keep in the fridge for 4-5 days. We like to store it in pyrex storage containers. It reheats well in the microwave or covered in the oven.
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- Serving suggestions – As this meal contains a lot of protein and veggies we find it is a complete meal. You can also serve it with additional veggies or a side salad if you prefer.
Nutrition Per Serve
I made this and it was quick, easy and delicious.
Glad you enjoy it Lainey
This tuna mornay is absolutely delicious. Such a beautiful satisfying meal and it takes me back to my childhood.
A real winner
Hey, thanks for the recipe. Just curious if this can be frozen once cooked?
Yes we have frozen it before and it freezes and reheats well
Every one I’ve made this for says it’s the best tuna casserole they’ve ever tasted. A family favorite now! Thanks so much!
So glad everyone enjoys it.
This is delicious! Just made this for dinner and my husband used his fingers to scrape the bowl and get the last drop of sauce! No judgment! Thanks for sharing. I will use the Mornay sauce recipe for other dishes too! Yumm-E
Did I miss what size pan?
In the post, there is a list of recommended equipment, We recommended at 9in size dish there.
This looked so good to me but when I went to make it I didn’t have any tuna and not enough broccoli. I substituted canned salmon I had for the tuna and used fresh asparagus that I had in place of the broccoli. It was delicious! Will definitely be making this very versatile dish again.
Thanks so much Sue – it is certainly a favourite!!
DELISH!!! I eat out at a restaurant that serves a fish dish with a Mornay sauce that has shrimp and crawfish in it and it is so good. I wanted to try a Mornay sauce at home. I found your recipe and decided to give it a go! I am low-carb, not Keto. I made a tuna casserole a few months back that I found online, and was so disappointed. THIS was the Bomb!
I made a couple of adjustments:
I chopped two celery sticks and sautéed in olive oil along with some chopped onions.
I used one bag of steamtable broccoli & cauliflower mix that was about 11 oz. (Measurements are different in the US, I guess)
1- 12 oz can of Solid White Albacore Tuna in Water, drained
Cook veggies in bag in micro for 4 minutes, let cool a minute or two, then drain.
Pour into greased casserole dish.
Top with celery & onion mixture
Spread a layer of cheddar cheese.
Spread the can of tuna.
Pour the Mornay sauce.
Finish off with another layer of cheddar cheese.
SOOOOO good. I’m a single person, so I had it for lunch for a few days after I had it for dinner. Was hard not to overeat and stuff myself.
Thank you for the GREAT recipe!!
Wow, thank you so much. It’s such a great recipe so we are glad you found it and loved it as much as we do.
This was so easy and very delicious. Next time, I’ll experiment with adding some different veggies. Definitely adding to my “easy weeknight dinner” rotation.
Thanks!
Yes, it is pretty versatile! People have also made it with tinned salmon or shredded chicken instead of the tuna.
Thanks so much Cassandra
I was really impressed with this casserole. Not only easy to make but was also delicious. Thank you!!
Easy and delicious – a great combination!
Thank you fir this recipe! Because I’m fancy 🤣, I added some crushed pork rinds with butter mix on top to make a little extra crisp. So delicious 😋. I appreciate you.
Oh great idea. Glad you enjoyed it.
I just made this and it is so delicious. I had to divide mine to 6 portions as it was way to much. I loved everything about this 10/10 ladies 🙂
Awesome! Thanks so much Selma
I made this with leftover fluke from the night before & it was fantastic! I had a friend drop over around dinner time & was a little nervous asking her to join me, as I wasn’t sure how this would turn out, but we both scarfed it down! I did serve it with a Caesar salad, which was the perfect accompaniment.
Awesome – love that!
I made this last week and it was amazing.
I didn’t blanch the Brocoli, Just threw it in was still lovely and crunchy. Did make it a tab watery, not much just a tad.
Was beautiful thank you for sharing your recipies.
Oh awesome – thank you!
Great recipe loved it
Thank you Mal! So glad you enjoyed it
Looking for some inspiration tonight. Found this recipe. This was absolutely divine! Thanks sooooo much
Thank you so much for sharing Catherine.
OMG have just started my journey and made Coconut Chia pudding for very late breakfast – I have trouble with’too’much to eat – then made Tuna Mornay actually with Salmon, didn’t have enough Broccoli so made up with Cauliflower rice – it is amazing , thank You so much for your ‘down to earth’ recipes.
Have all your books and can’t wait
Try the rest – Min
So glad you enjoyed it and thank you so much for buying all our books. Have fun cooking all the yummy recipes.
Made this for dinner tonight, with cauli and a couple of peas for colour.
The family loved it, and are keen for the cheese sauce to make an appearance on top of vegies.
So glad the family loved it Silvia!
I didn’t have enough cauliflower so ended up using a combo of cauliflower and broccoli. Absolutely delish! That sauce is the bomb! Thank you!
I agree. That cheese sauce is amazing
So good! I made mine with cauliflower and it was simply delicious!!! I will definitely make this again!
Awesome. So glad you like it
My husband loved this recipe but your recipe must be cursed because when he was putting the leftovers away he dropped everything broke the casserole dish and wasted all the leftovers! We will be making this again but carefully!
Oh no. I’m not sure if you have seen in the post but one of our cats caused this tuna mornay to crash all over our floor while Erika was making it. So maybe you are right. It might be cursed.