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!

4.8 from 4 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 part of the blogging duo behind Autoimmune Wellness. She helps others take charge of their health the same way she took charge of her own after suffering with Celiac and other autoimmune diseases; one creative, nutritious meal 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’s also a world traveler who has been medically evacuated from two foreign countries. Strategizing worst-case scenarios is now something of a hobby. She is a Certified Health Coach through the Institute for Integrative Nutrition and author of The Alternative Autoimmune Cookbook: Eating for All Phases of the Paleo Autoimmune Protocol. 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.

  • 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: http://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?

  • 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?

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