
Tuna mornay is a retro classic. We remember growing up having this with our families. This keto tuna mornay will have you reminiscing the good old days. This keto tuna casserole recipe would be great for low carb families, as it is an excellent kid-friendly option.

Keto Tuna Mornay
Both Erika and I were brought up on our own family versions of tuna mornay. Our family had this dish called crusty tuna rice. It was similar to tuna mornay but it has a breadcrumb topping and cooked rice mixed through the tuna and cheese sauce mixture. It was definitely a theme in my family, double carb everything! I was really happy when Erika made this version of keto tuna mornay as it reminded me of my childhood and it is also super delicious.
This keto tuna casserole recipe has become a big favourite with our friends and family. Erika’s mum likes to make it for us when we come to visit. We recently moved back to Newcastle and had to live with them for a few weeks and we ate this keto tuna mornay about once a week. I also love to take any leftovers for lunch the next day.
My mum has also made this keto tuna casserole recipe a few times and raves about it to anyone that will listen. A perfect low carb recipe that is family and kid friendly.
Tuna Mornay versus Tuna casserole
We have learnt so much since starting our keto way of life and one of the things we have had to get used to is the Australian versus American names for things. To Australians a casserole is a slow cooked stew consisting of some sort of protein like beef and a gravy type sauce. It took as a while to realise casserole in North America is a oven baked dish that has more of a creamy, cheesy or egg base.
If you are from North America and a little confused by keto tuna mornay, it is essentially a keto tuna casserole. Just by a different is the name!

Tuna and our cats
Our two rescue cats, Scout & Gem, love their tinned fish. As soon as we open a can they emerge from wherever they are sleeping at record speed. So I shouldn’t really be surprised that when I was trying to photograph our yummy keto tuna mornay for the website and turned my back for 2 seconds it ended badly.
So please note: Don’t leave unattended with keto kitties around!

Tips
- If you prefer you could swap the broccoli to cauliflower or another vegetable you have on hand. We like it with a combination of broccoli and cauliflower.
- Try to purchase tuna in spring water or plain olive oil to avoid any inflammatory vegetable oils. Tinned salmon would work well in this too if you have that available instead.
- You can find our super quick and easy Keto Cheese Sauce recipe here.

Suggestions
- The best thing about this keto tuna mornay is that there is no need to serve it with a side. It is a full meal all in one.
- This keto tuna mornay is a perfect family-friendly meal and even your non-keto family will love it.
Equipment
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You may need –
Keto Tuna Mornay
One of the things I love about this recipe is it’s my favourite way to eat tinned tuna. We definitely don’t eat enough seafood in our diet and this keto tuna mornay is my favourite. It’s 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 flavour and creaminess of this keto tuna mornay recipe. Once you have the cheese sauce made it is as simple as putting it all in a baking dish and topping with cheese and baking in the oven.
Let us know in the comments below how much you and your family loved this recipe!
If you like this recipe, please give it a 5 star rating.
If you like this recipe you may also like…
- Mexican Chicken Salad
- Mexican tuna salad
- Tuna Salad without Mayo
- Panko Chicken
- Cream Cheese Pasta
- Lemon Chicken Marinade
- Mexican chicken marinade
- Smoked Chicken Salad
- Roast Pumpkin Salad
- Tandoori Chicken Salad

Ingredients
- 1 batch keto cheese sauce
- 400 g broccoli florets (14 oz)
- 425 g tin of tuna, drained (15 oz)
- 100 g cheddar cheese, grated (4 oz)
Instructions
- Preheat oven to 180C/350F
- 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
NOTE: THIS IS BASED ON THE INGREDIENTS WE USED, NUTRITIONAL INFORMATION MAY VARY DEPENDING ON THE INGREDIENTS USED.
Nutrition Per Serve
Just made this tonight and it was delicious! I’ve tried a few keto casseroles and this is the first one that didn’t feel like I was just eating a bunch of butter and cheese (even though there was a hefty amount of cheese :P) . Loved the big chunks of broccoli and that keto cheese sauce is so goooood.
Thank you so much Bhumi. We are big fans of that cheese sauce too. We haven’t had this Tuna Mornay for awhile and we have added to the dinner list for this week.
Omg just had this for dinner… sooo yummy! Just the right amount of tuna and broccoli to cheesyness. Definitely a new favourite!
Thank you so much for your comment Rachel! So glad you enjoyed it. One of our favourites too
Wow!!! This was absolutely D-E-L-I-C-I-O-U-S!! Thank you so much for sharing this recipe ❤️ Fussy kids and husband demolished it ?
That cheese sauce… I have no civilised words for how good it is haha.
So glad you enjoyed the tuna Mornay. We tried to give it to our niece and nephew and they were not interested. They must be even fussier than your kids.
Does this really have 10 g. of carbs? I don’t see hwere they are coming from.
Yes it has 9 total carbs and 7 net. The carbs comes from the broccoli, all the cheeses and the cream in the cheese sauce. Cheese and cream have a small amount of carbs and they all add up in this recipe. We were actually shocked when we made it as to how many carbs it had.
Yes, Yummy!! Thank you for this fast dinner.
I found that 4 servings was way too much too eat and divided my casserole dish into 8 servings. I rarely eat a/4 head of broccoli in 1 meal :), so my net carbs are 3.8.
Sounds perfect. Glad you enjoyed it.
Made this tonight and it was soupy. Where did I go wrong? The flavor was amazing.
Hi Emily,
A couple of things may have happened. Was the cheese sauce thick when you added it to the tuna and vegetables? If not, the sauce needed to thicken on the stovetop more. If it was, it may have been from water coming out of the vegetables. We usually use broccoli and this hasnt been an issue for us. Another tip from Erika would be to maybe let the dish sit for 5 minutes when you take it out of the oven before serving. Also, make sure you have drained the tuna well before putting it in the baking dish. Hope this helps.
Thanks Dan
I made this recipe last week. Let me tell you, it was so delicious my husband and I ate the whole thing! Wow!! Thank you for the super, awesomely delicious recipe. I think my tastebuds were secretly singing. ? This will definitely be a recipe we keep. ?
So glad you liked the tuna Mornay. It’s my favourite way to consume the cheese sauce, which is delicious.
This looks wonderful! I plan on making this tonight.
It’s really good. Hope you enjoy it.
This was delicious!
Thanks Brooke.
This is a weekly favourite in our home now! It’s so quick and easy!
I steam the broccoli in the thermomix at the same time as the cheese sauce is cooking and then throw is all in oven.
It’s so quick and nutritious and the whole family love it and they’ve stopped asked about the tuna pasta we used to eat in my pre-keto days!!!!
I love stories like this. Thanks Narelle.
We loved this tuna mornay. Even my non-keto other half like it, said it was ‘nice and cheesy’. He didn’t even miss the pasta and corn that I used to make it with! That cheese sauce makes everything better 🙂
I agree, the cheese sauce is the highlight of this recipe.
This is delicious. A weekly offering in our house. A childhood memory now in the keto world. Winner winner Tuna dinner.
Love it. Winner winner tuna dinner.
Where do I get the cheese what kind of cheese do I get
We just use tasty or cheddar cheese from the supermarket.
I was looking for an easy keto cheese sauce, and happened upon the Tuna Mornay. I got a twofer, a great tasting cheese sauce and a delicious casserole. Thanks for sharing your recipes.
I love that. A twofer!!!
This is delicious my second time making it we love it ?
Thanks Cindy.
This is fantastic! Made it for lunch today. Will definitely be making again. Thanks for a great recipe!
Awesome. Thank you.
Hi, so I just want to know if the Nutritional Facts are based on both the Tuna Bake and/with the Cheese Sauce together or separately? ?
It is delicious!
The nutritional info includes both.
This was absolutely delishious. I never like tuna casserole while growing up. However, I’m now low carb and looking for keto comfort food. This fits the bill perfectly. Thank you! ( And I can see other usesfor that cheese sauce going forward!)
We absolutely love this recipe. We have been having it a bit lately.
Made this for dinner and it was delicious! Kids also loved it. Will definitely be making again!
It’s delicious
Love this! So quick, easy and delicious ?
Thanks Lynda
love at first bite (well, first lick- I licked the sauce pot clean! ?) I love love LOVE this recipe! thanks so much for such a yummy dinner! I will make mushroom and onion cauliflower rice to go with it next time! ?
So glad you love this recipe. It’s definitely one of our favourites
Super easy and really delicious for keto and non-keto family members.
Thanks so much julie
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.
So good! I made mine with cauliflower and it was simply delicious!!! I will definitely make this again!
Awesome. So glad you like it
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
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!
Looking for some inspiration tonight. Found this recipe. This was absolutely divine! Thanks sooooo much
Thank you so much for sharing Catherine.
Great recipe loved it
Thank you Mal! So glad you enjoyed it
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!
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 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
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 was really impressed with this casserole. Not only easy to make but was also delicious. Thank you!!
Easy and delicious – a great combination!
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
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 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!!
Did I miss what size pan?
In the post, there is a list of recommended equipment, We recommended at 9in size dish there.
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
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.
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
This tuna mornay is absolutely delicious. Such a beautiful satisfying meal and it takes me back to my childhood.
A real winner
I made this and it was quick, easy and delicious.
Glad you enjoy it Lainey
Such a yummy recipe! The only way I eat broccoli. Thank you.
Easy to make and very tasty.
It is a nice easy one isn’t – thanks Lisa!