Tuna Cauli Casserole

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You know what I like? I like casseroles. ‘Cause easy, comforting, and delish! I’ve been working on an AIP-ified tuna casserole for you guys forever and I finally have it ready for you. There are no gluten-y noodles, just yummy veggies. And there’s no can of cheap cream of mushroom soup, just a creamy sauce without wheat or dairy (yes! I perfected it!). Here’s to casual, inexpensive weeknight meals with all the goodness baked into them!

4.9 from 20 reviews
Tuna Cauli Casserole
Prep time
Cook time
Total time
Serves: 4
  • 1 large head cauliflower, chopped into florets
  • 1 cup packed arugula
  • 1 yellow onion, diced
  • 2 garlic cloves, minced
  • 3 stalks celery, diced
  • 1 tablespoon minced fresh thyme
  • 1 teaspoon sea salt
  • 4 tablespoons palm shortening, divided
  • 5 tablespoons cassava flour
  • 1 can full-fat coconut milk
  • ½ cup chicken bone broth
  • 2 5 oz. cans undrained, water packed tuna
  • Fresh parsley, for garnish
  1. Preheat oven to 375 degrees F. Grease a 9x13 casserole dish with small amount of palm shortening.
  2. Add cauliflower to a large pot and bring to a boil. Remove from heat after 4 minutes, drain water and layer cauliflower into bottom of prepared casserole dish.
  3. Layer arugula over cauliflower and set aside.
  4. In a large heavy-bottom skillet, melt 1 tablespoon palm shortening over medium heat. Add onion, garlic, celery, thyme, and salt, and cook until onion is softened, about 8 minutes.
  5. Remove vegetable mixture from skillet to a clean bowl and set aside.
  6. In the same skillet, melt remaining 3 tablespoons palm shortening over low heat. Add in flour and quickly whisk until mixture just begins to bubble. While continuing to whisk, slowly pour in coconut milk. Whisk until a smooth, thickened sauce forms.
  7. Add vegetable mixture and broth to sauce mixture. Stir to combine.
  8. Remove sauce from heat, stir in tuna with canning liquid.
  9. Pour sauce over cauliflower and arugula.
  10. Bake covered for 15 minutes, remove cover, turn oven up to 425 degrees F, and bake for 12 more minutes or until casserole begins to lightly brown.
  11. Garnish with parsley and serve.


About Angie Alt

Angie Alt is a co-founder here at Autoimmune Wellness. She helps others take charge of their health the same way she took charge of her own after suffering with celiac disease, endometriosis, and lichen sclerosis; one nutritious step at a time. Her special focus is on mixing “data with soul” by looking at the honest heart of the autoimmune journey (which sometimes includes curse words). She is a Certified Health Coach through the Institute for Integrative Nutrition, Nutritional Therapy Consultant through The Nutritional Therapy Association and author of The Alternative Autoimmune Cookbook: Eating for All Phases of the Paleo Autoimmune Protocol and The Autoimmune Wellness Handbook. You can also find her on Instagram.


  • Meghan says

    Hi Angie! I’d love to try this, but is there anything I can sub for the cassava flour?

    • Angie Alt says

      Hi Meghan-
      I find the cassava flour blends best for a roux base to make a cream sauce, but you could certainly try experimenting w/ some of the other AIP-friendly flours.

      • Pam says

        Could you include macro breakdowns plz

        • Angie Alt says

          Hi Pam-
          I believe you could plug this recipe into a site like Cronometer to get macros.

  • Caroline says

    Hi Angie,

    This looks great! One question: you mention canning liquid from the tuna. Does that mean you use tuna canned in water?

    Haven’t been able to find white palm shortening here in Europe. Mine is bright orange. Maybe I’ll add some nutritional yeast and pretend it’s cheese 🙂

  • Dimitrina says

    Hi Angie! Saw this the other day and decided to make it. It was wonderful! It instantly took me back to childhood memories of tuna casserole (the not-so-good-for-you kind). Thanks so much for the recipe, I can see this becoming a favorite 🙂

    • Angie Alt says

      Hi Dimitrina! I am sooo glad to hear that. I used to love me some of the “not so good” kind too. Enjoy!

  • Alycia says

    Do you prefer to use tuna in oil or water?

    • Alycia says

      I ended using tuna in water as I felt the tuna in oil would make the dish too, well oily:) It was really good and reminded me of eating tuna casserole as a child. I did forget to add the coconut milk to the rue but added it to the casserole before I put it in the oven. That’s what I get for not carefully reading the instructions!!It was really good. Can’t wait to try it again.

  • Karen says

    Made this and it was yum! Husband really enjoyed it too, and he’s not AIP. But…I am wondering – would it possible to delete the coconut milk and sub it with another liquid? Any ideas???
    Also, just fyi: to make life easier, I used packaged Pacific TURKEY bone broth; it’s AIP ready to go and even comes in large and small containers: https://www.pacificfoods.com/food/broths-stocks/bone-broths/organic-bone-broth-turkey.aspx

    • Angie Alt says

      Karen, I’m sorry, but I really don’t know a good sub. You could try to use broth, instead of coconut milk & see if it gets the same consistency.

  • Theresa says

    I just made this and it was awesome!! The roux with the cassava flour and oil worked great. Thank you for this recipe!!

  • Anthea says

    Please, please don’t use palm oil or anything made from it. The rainforests of the world are being destroyed by the palm oil industry with the ensuing loss of valuable species – some of which we have not yet researched. Any artificial shortening of this sort requires processing which is not good for us and it is possible to make a perfectly good and delicious sauce from an organic oil. Other than this the recipe sounds delicious!

  • Jennifer Araujo says

    Hi what could I use instead of coconut – I love the taste but react to it…thanks!

    • Angie Alt says

      Jennifer, I’m sorry, but I really don’t know a good sub. You could try to use broth, instead of coconut milk & see if it gets the same consistency.

  • Christie says

    Hi Angie! This looks & sounds DELICIOUS! I, too, am casserole obsessed & miss them desperately on AIP, so this made my heart go pitter-patter. 😉 I am also wondering about the tuna – canned in oil or water? I’m imagining it could make quite a difference in both taste & texture, so I’d like to know what you use. Thank you!😃

    • Angie Alt says

      Hi Christie, I used canned in water. Yes, that is too much oil if you use canned in oil.

  • Victoria says

    Hi! This looks great, but is there anything I can use instead of the coconut milk? I tend not to do great with coconut. Thanks!

    • Angie Alt says

      Victoria, I’m sorry, but I really don’t know a good sub. You could try to use broth, instead of coconut milk & see if it gets the same consistency.

  • Gordeen Darbee Sherwood says

    I don’t eat tuna, could I use canned chicken instead? Thanks

    • Angie Alt says

      Sure, Gordeen, it would probably be yummy. I might consider just dicing up some organic chicken thighs in that case.

  • Robyn says

    Do you have the nutrition facts for this recipe?

    • Angie Alt says

      No Robyn, sorry, we aren’t able to do testing like that, but you could probably look up the general nutrition facts for each ingredient to get an idea.

  • Cindy says

    Hello, can tigernut flour be used instead of cassava flour?


    • Angie Alt says

      You try it, but I suspect it will not produce as smooth a sauce. Thanks!

  • kellie says

    What could you use other than palm shortening?

    • Angie Alt says

      Kellie, palm shortening a good sub for butter, which is used in making a traditional roux base for a creamy sauce. You might come out okay w/ coconut oil, but I have not tried it.

  • Angela says

    This was delicious! Try drizzling the juice of 1 lemon and sprinkling its zest over top of the dish once you pull it out of the oven!

    • Angie Alt says

      Ooooh! Angela, that’s a great suggestion. Thanks for sharing.

  • Michelle says

    Thanks so much Angie. I made this today exactly as stated in the recipe. No subs. It was delicious!

  • Lacy says

    Does this dish freeze and reheat well?

    • Angie Alt says

      Lacy, see my instructions in reply to Renee below.

  • Patty says

    Has any one tried freezing this?

    • Angie Alt says

      Patty, see my instructions in reply to Renee below.

  • Renee says

    I just made this and must say…you nailed this recipe! Delicious, comforting and satisfying. Thanks for posting!

  • Patty says

    At what point do you add the bone broth!?!

  • Allison Hanley says

    I love this dish! Made it twice now. Tastes the same as non-AIP tuna casserole to me. Thanks for your hard work in creating this recipe!

    • Angie Alt says

      You are so welcome Allison! Glad you loved it!

  • Renee' Arnold says

    I was just wondering if this casserole would freeze well, either before or after cooking? I’m always lookinf for make-ahead meals. 🙂

    • Angie Alt says

      Yes, Renee, you can freeze it after cooking. Here’s some instructions:

      Freezing instructions:
      1. Allow dish to cool to room temperature.
      2. Cover with a tight layer of plastic wrap, following by a tight layer of aluminum foil.
      3. Write the date and recipe name on the foil.
      4. Place in freezer for up to 2-3 months.

      Serving day ingredients:
      ” Fresh parsley, for garnish

      Serving day instructions:
      1. Take dish out of freezer and place in the refrigerator to defrost overnight.
      2. Preheat oven to 375 degrees F. Remove inner plastic wrap lining and recover with aluminum foil.
      3. Bake covered for 25 minutes, remove cover, turn oven up to 425 degrees F, and bake for 12 more minutes or until casserole begins to lightly brown.
      4. Garnish with parsley, serve and enjoy!

  • Swan says

    This continues to be one of my favorite recipes for my new AIP lifestyle. Thank you!

  • Amanda says

    I’ve been wanting to try this and I finally had a chance to make it. The whole family approved! It was so nice to have a casserole again. I made the mistake of adding more salt to the vegetable/roux mix and didn’t consider that the canned tuna would add additional salt flavoring, so I’d advise to not add more salt until you’ve tasted it after the tuna is added. Even with a tad too much salt it was still really good. The only thing I didn’t care for is this did take me far longer to prep than I had expected. I wonder if I subbed whole cauliflower and used fresh riced cauliflower that you can now get at the supermarket if that would work even if I didn’t pre-steam it? Has anyone tried it this way?

    • Angie Alt says

      Glad you loved it Amanda! I’m not sure about the cauli rice. I think you might get a too mushy consistency, but you could certainly give it a shot!

  • Elise says

    You didn’t list the directions of water and boiling the cauliflower.

  • Gabrielle Boswell says

    Really enjoyed this dish. Thanks so much. Comforting but not heavy 🙂

  • Annika says

    Could gelatin be used to thicken instead of cassava flour? We are brand new to this diet, and I don’t have any cassava flour. I can order it or find it at whole foods or something eventually, but I want to make this now. Ha!

  • Susan says

    Just finished having this casserole for lunch. Husband and I absolutely loved it. I’ve never eaten a Tuna Casserole before, but this one was perfect. Prep time took me much longer than the 25 minutes, but then, I’m not a cook. So glad this worked out great for all the effort. Thank You.

  • Denise says

    It looks delicious! Just wondering what size can of coconut milk? They tend to come in different sizes here in Australia 🙂

    • Mickey Trescott says

      Hi Denise! I think Angie will chime in too to be sure, but most cans of coconut milk here are 14 1/2 ounces.

  • Marcia says

    Damn – this is delicious. It’s like going home…. LOL Seriously, comfort food at its best! Mine turned out very orange – my palm fat must be different than yours. And I used a half pkg of Trader Joe’s Power to the Greens instead of arugula to save a trip to the store. Absolutely delicious. And definitely scratches the tuna casserole itch. Thanks so much for developing this recipe!

  • Luke says

    An absolute hit! I do all of the cooking and my partner is going on an AIP diet. Much as I enjoy a challenge I was a bit apprehensive at first, but this recipe and result has given me hope! I may make some small tweeks in future to keep things varied such as adding bacon to the sauce perhaps, or subbing the tuna out for salmon however that will only be in the pursuit of variety, not because the dish necessarily needs anything more added!

    • Angie Alt says

      Hooray! I am so happy this worked for you guys, Luke!

  • Kath Milkovits says

    Thank you very much for this yumminess, my belly is now a very happy place 🙂 I wondered how many days something like this would keep refrigerated? Ive never made Tuna Casserole before!

    • Angie Alt says

      If it’s properly refrigerated & covered, I think you can keep it for 2-3 days. It is also possible to freeze.

  • Kira says

    This was absolutely wonderful! Thank you so much for everything you do to make taking care of our health so much easier. <3

    • Angie Alt says

      You are so welcome, Kira! Glad you loved it!

  • Shelley says

    This was wonderful! Even my husband who turns up his nose at many of the things I make on my diet liked this and said you can make this again-I rarely hear that!
    Your labor paid off. I so appreciate you ladies and all of the recipes and information you share.
    When I was first diagnosed with Auto-Immune disease last August, I thought [just like I did when needing to go GF/DF 6yrs. ago] What will I eat now?

    But all of you are such a blessing! I have shared your site with my chiropractor and functional medicine doctor and they are sharing with other patients.
    Thank you for all you do!

    • Angie Alt says

      Shelley, I’m so glad it was such a big hit & that your healthcare team loves our resources too! Thanks for sharing w/ them.

  • Clarissa says

    Fantastic! I loved tuna noodle casserole as a kid and was very happy to find a dairy free gluten free alternative. Kids and hubby loved it! Thank you!

  • Marcia says

    Sadly, I’ve recently determined that I am sensitive to cassava flour. Has anyone tried subbing a different flour? The cassava worked so well – not sure what other flours might work that way.

  • Liz says

    I used coconut oil and it still came out great. Classic tuna casserole taste and texture. I think next time I will add asparagus!

  • JenFW says

    I look forward to trying this with peppery arugula when I have some. I substituted kale, but it was still delicious. We’ll be making this again. Thank you!

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