This keto tuna casserole is made with mushrooms and spinach and is packed with two types of cheese - making it the ultimate cheesy tuna casserole! And it's not only flavorful & creamy, but it's nutritious too. Honestly, this might just be one of the best keto casserole recipes you can make.
THE BEST KETO TUNA CASSEROLE
This low carb tuna casserole has everything that makes a great keto recipe.
It filled with keto-friendly vegetables, creamy melted cheese, has a ton of flavor, and yields multiple servings.
And of course, it's a low carb tuna casserole! There's only 3 NET CARBS per serving.
Also, this keto tuna casserole is loaded with nutrients and it is gluten free, making it a super healthy meal.
Tuna is not only a great source of protein but it's also an excellent way to get your daily dose of omega-3 fatty acids and vitamin B6. Top that off with the mushrooms and spinach, and you've got yourself one super healthy dish.
Plus, this low carb keto recipe is incredibly quick and easy to make, and you can have it ready and on the table in under 30 minutes.
Oh, and if you're looking for more low carb casseroles, check out this asparagus casserole and cheesy spinach casserole next!
INGREDIENTS FOR KETO TUNA CASSEROLE
Now, typically, tuna casserole is made with bread crumbs and noodles, causing the dish to have upwards of 60 grams of carbs per serving.
For this low carb tuna casserole though, we will be using almond flour in place of bread crumbs to keep the carbs down but still give this casserole a crispy, crunchy surface, just like with these keto chicken nuggets.
Also, we'll be using mushrooms instead of noodles to make this recipe even more low carb and gluten free.
Having said all of that, here's the complete list of things you'll need to make this low carb keto casserole:
- 2 tbsps butter
- ½ onion, chopped
- 2 cups sliced mushrooms
- 1 cup chopped spinach
- 2 five ounce cans of tuna packed in water, drained
- 1 cup grated mozzarella cheese
- 1 cup cream cheese, cubed
- 1 teaspoon Italian seasoning
- Salt and pepper to taste
- 2 cups shredded Cheddar Cheese
- 2 tbsp almond flour
Combining the ingredients in this recipe makes this casserole irresistibly delicious and turns regular tuna casserole into super healthy comfort food.
And it's easy to make, and even easier to clean up.
So you know I'm a big fan of that.
GRATE YOUR OWN CHEESE
We are going to be using mozzarella and cheddar cheese to give this tuna casserole its delicious cheesiness.
Although both of these cheeses come pre-shredded, I recommend shredding your own cheese with a cheese grater.
The pre-shredded cheeses that you can buy at the store typically have added starches in them.
The added starches prevent the cheese from clumping and sticking together. But, these starches contain unnecessary carbohydrates.
So, to keep your keto tuna casserole - and other low carb recipes - as low carb as possible, avoid the pre-shredded kind.
Now, if you already have the pre-shredded cheese on hand or don't want to buy a block of cheese, don't worry. This dish is already super low in carbs, thanks to the rest of the ingredients, so feel free to use it.
By the way, to make this even cheesier, you can sprinkle some parmesan cheese on top after it gets out of the oven.
ARE MUSHROOMS KETO?
As I mentioned earlier, we will be using mushrooms in place of noodles for this tuna casserole.
Now, mushrooms tend to get overlooked and not many people realize just how great they are for keto.
In fact, mushrooms might be the best low carb keto "vegetable" you can have.
First off, mushrooms are super low in calories and carbs. Each cup has about 16 calories and a low carb count - about 1.5 grams.
Secondly, mushrooms are packed with fiber and water, making them a "bulk" food. And this means that they can make you feel full without eating a lot of them.
Plus, mushrooms are high in potassium, which is an essential mineral and electrolyte. And potassium is vital on the keto diet because your body flushes out a lot of water since you are not eating carbs to retain it.
So, the verdict is that mushrooms are keto friendly, and one of the best keto foods you can eat.
Mushrooms to use for this casserole
Ok, so we know mushrooms are perfect for this low carb tuna casserole, but what mushrooms should you use?
There are various mushrooms to choose from, and you really can use any ones you want.
With that said, I suggest using sliced white or brown button mushrooms, cremini mushrooms, or mini-portobellos.
I think these mushrooms pair best with the overall flavor in this tuna casserole.
HOW TO MAKE KETO TUNA CASSEROLE
Ok, so now let's get into the nitty-gritty on how to make this low carb keto casserole.
One of the reasons I love this gluten free casserole is that it only requires a few steps and it is so quick and easy to make.
All you have to do is sauté the vegetables, incorporate the rest of the ingredients, then bake everything in the oven, and you'll have yourself a delicious casserole ready to go.
Now, if you're ready to make this recipe, let's get to it!
STEP 1: PREP
First off, you'll want to preheat your oven to 350°F (176°C) and coat a 9x9 inch baking dish with cooking spray.
Next, you'll want to prepare the vegetables. Chop the spinach and onions, then slice the mushrooms.
STEP 2: SAUTE THE VEGETABLES
Now we're all set to start sauteing our vegetables.
So, to begin the sauteing process, you'll want to melt the butter in a large pan over high-heat.
Next, add the onions and saute for 3 minutes. Then, once the onions have softened, add the mushrooms.
Cook the mushrooms for about 5 minutes on high-heat to reduce the moisture in them. And make sure you stir the mushrooms often while cooking.
Lastly, add the spinach, stir them until they're wilted, and turn the heat down to low.
STEP 3: COMBINE ALL THE INGREDIENTS
Now you're all set to add the cream cheese, grated mozzarella, Italian seasoning, salt, and pepper to the pan.
Cook everything and stir until the cheese just starts to melt and combines with the other ingredients.
After that, add the drained tuna and stir together until everything is combined.
STEP 4: ASSEMBLE AND BAKE
So, at this point, you'll want to spoon the tuna mixture evenly into the baking dish.
Then, sprinkle the shredded cheddar on top, followed by the almond flour.
Bake for a total time of 15-20 minutes, or until the surface is crisped and golden brown.
Let it cool for a few minutes in the baking dish, sprinkle some parmesan cheese on top, and then this casserole is ready to serve!
STORING YOUR KETO TUNA CASSEROLE
While low carb tuna casserole is best enjoyed fresh, this recipe makes about 10 servings, giving you a delicious leftover meal for the next few days.
You can store your leftovers in an airtight container in the refrigerator for up to 3 days. If your baking dish has a lid to it, simply pop it on and put the casserole dish in the fridge.
For reheating the refrigerated casserole, put it in the oven at 350° F (176°C) until warm, about 20-30 minutes, then sprinkle some grated parmesan on top and dig in!
FREEZING YOUR CASSEROLE
You also have the option to freeze this casserole if you would like for it to last longer.
It can be frozen for up to 6 months, as long as you store it in an airtight, freezer-safe container.
To reheat the casserole that has been frozen, you have two options.
First, you can let it thaw in the fridge, then reheat in the oven at 350°F (176°C) for about 20-30 minutes until it reaches your desired temperature.
However, you can also reheat frozen tuna casserole directly in the oven, though this will take significantly longer, sometimes up to an hour.
Just make sure that you let your frozen tuna casserole come to room temperature before popping it in the oven to avoid the dish's glass breaking due to extreme temperature change.
Also, it can be reheated in the microwave, but you may lose some of the crunchiness on the surface layer you get when baking and reheating in the oven.
As I mentioned above, this gluten free and keto tuna casserole has just 3 NET CARBS per serving. Pretty good for a dish that traditionally has a super high carb count.
So, this recipe makes a 10 serving casserole, but the full nutritional information for 1 serving is as follows:
- 239 Calories
- 19g Fat
- 4g Carbs
- 1g Fiber
- 3g NET CARBS
- 14.4g Protein
Now, since this recipe makes so many servings, it is a great meal to make and have on hand for lunch or dinner the next couple of days. Meal prep anyone?!
Or, if you want to make this dish for a family dinner, you'll easily be able to feed everyone.
And trust me, they'll enjoy this low carb tuna casserole just as much as a non-keto tuna casserole.
Anyway, I hope you like this keto tuna casserole as much as I do, and if you try it out, let me know what you think in the comments below.Print
Keto Tuna Casserole | One of The Best Keto Casserole Recipes
This keto tuna casserole is made with mushrooms and spinach and is packed with two types of cheese - making it the ultimate cheesy tuna casserole recipe! It's not only flavorful & creamy, but it's nutritious too. And, honestly, it might just be one of the best keto casserole recipes you can make.
- Prep Time: 15 minutes
- Cook Time: 15 minutes
- Total Time: 30 minutes
- Yield: 10 servings 1x
- Category: Dinner
- Method: Stovetop/Oven
- Cuisine: Keto Low carb
2 tbsps (28g) butter
½ onion (60g), chopped
2 cups (200g) sliced mushrooms
1 cup (30g) chopped spinach
2 five ounce cans of tuna packed in water, drained
1 cup (112g) grated mozzarella cheese
1 cup (113g) cream cheese, cubed
1 teaspoon Italian seasoning
Salt and pepper to taste
2 cups (224g) shredded Cheddar Cheese
2 tbsp (28g) almond flour
- Preheat the oven to 350°F (176°C) and coat an 9x9 inch baking dish with cooking spray.
- Chop the spinach and onions, then slice the mushrooms.
- To begin cooking, melt the butter in a large pan over high heat. Add the onions and saute for 3 minutes.
- Once the onions have softened, add the mushrooms and cook for about 5 minutes on high heat, stirring often.
- Now, once the mushrooms have softened - and reduced in size - add in the spinach, stir until wilted, and then turn the heat down to low.
- Then, when the spinach has wilted, add the cream cheese, grated mozzarella, Italian seasoning, salt, and pepper to the pan.
- Cook everything until the cheese just starts to melt and combines with the other ingredients.
- Then, add the drained tuna and stir together until everything is combined.
- Once everything combines, spoon the tuna mixture evenly into the casserole dish.
- Sprinkle the shredded cheddar on top, followed by the almond flour.
- Bake for 15-20 minutes, or until the surface is crisped and golden brown.
The scale up function does not change the gram measurements.
- Serving Size: About ⅓ a Cup
- Calories: 239
- Fat: 19
- Carbohydrates: 4
- Fiber: 1
- Protein: 14.4.
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This was delicious!! My family really enjoyed the casserole.
This is a very easy and delicious low carb casserole recipe.
Oh my gosh…. The absolute most delicious tuna casserole EVER! My adult son who claims he doesn’t like onions or spinach ate half the casserole in one sitting. I didn’t even make it for him. I wouldn’t change a thing about this. Amazing
So glad you two liked it!
My favorite keto casserole that I have tried! Delicious!!
Super delicious casserole recipe! Had a great balance of textures and falvors.
Great casserole for keto. Family loved it too!
Everything about this recipe is a plus. It was easy, fairly quick, and the casserole turned out perfect.
Loved it. Will make again and I recommend it.
This is as good as it gets for a keto casserole1
Really liked this recipe, I am going to make it again.
My family loved this.
Made this for our Sunday family dinner, and had no leftovers. This recipe is 💯
My family (kids included) like this a lot!
If anyone wants a easy recipe that will feed a few people this tuna casserole is a great make!
The crispy top and cheesy flavor is delightful.
It was easy to make and tasted tasty!
Glad you liked the recipe!
Wonderfully done casserole!
I love that this uses almond flour to create the crunch. I can't stand recipes that only use pork rinds!
Probably the best dinner that I have made so far on keto.
The cheesiness and crunch this casserole has is incredible.
I ended up making this over the weekend and my family loved it!!
One of the best kept casseroles I’ve made.
I really enjoy this for dinner!
I'm not even a big tuna fan and I thoroughly enjoyed this casserole.
My go to dinner recipe lately I really like this casserole.
10 out of 10
Wow was this ever good! After reading other's comments I felt I had to make this casserole and I was not disappointed. Not only is it easy to throw together in a few minutes but the flavors are amazing! I used frozen spinach as it is what I had on hand but otherwise followed the recipe. It is so good and flavorful. I know this will be on my dinner rotation often.
Actually my family's favorite keto dinner recipe that I have made so far. It's a keeper!
Very good casserole that doesn't taste low carb.
i don't like mushrooms so I left them out but this was very very good.
Wow it was a good one.
This is my fav keto dinner!
Hi ya'll! Make this if you want a big dinner your family can eat. Mine loved it and said they wouldn't have know it was keto!
This was splendid.
Better than expected. A delicious casserole.
Is it possible to use yellow fin tuna in olive oil for this? Our tuna in cans is not the best here in Norway.
Hi Zalinda, yes that should work great!
Gave it a try and to my surprise my family loved it!!
My usual tuna casserole is loaded with noodles, and my kids didn't usually like it.
I didn't even miss the noodles with this recipe and my kids all gave 2 thumbs up, asking for seconds.
I upped the recipe to the 2x for my family of 5, it was just hardly enough. Next time I think I'll up it to 3x.
That's great!! We're so happy everyone liked it 🙂
This Tuna Casserole is VERY good. Being Keto just makes it better! I do have one question. Why on earth are you specifying a 9" x 13" baking pan? I used two 7oz cans of tuna instead of 5 oz as specified in the recipe and I added more mushrooms and extra cream cheese and, honestly, I had a hard time spreading out the casserole to even cover the bottom of pan. My casserole was barely 1/2 inch thick! Did I miss something? A 9" x 9" pan would have been much better and I'm pretty sure and 8" x 8" pan would have worked well too. I'll be making it again, but will use a MUCH smaller pan!
We're so happy you like the casserole!! Sorry about that, yes, a 9x9 works better.
OMG, I can't believe you actually answered me!! Thanks for letting me know I haven't lost my mind. I'm 76 years old and sometimes we're just not sure!?!?!? Again, SUPER GREAT recipe (with a 9x9 pan).
Of course! Thanks for the pan size suggestion and so happy you liked the recipe 🙂
I love this. So good!!! Easy directions to follow
I will make it again