Spaghetti Squash Tuna Casserole

Spaghetti Squash Tuna Casserole

I think most of us know by now that spaghetti squash makes a great substitute for pasta.  Well, this tuna casserole is no exception.  If you grew up with the “classic” tuna casserole (noodles, cream of mushroom soup, tuna and canned peas), then this casserole will bring back old memories but with a new and healthier twist! 

Note:  I happen to love ginger so any opportunity I can take to add it to a dish, I will!  If you don’t have fresh ginger, substitute a teaspoon or so of ground ginger or there is always the option of omitting it all together. 


  • 1 large spaghetti squash, cooked and shredded
  • 3 small sized cans of tuna (wild caught variety)
  • 1 can diced green chilis
  • ½ cup approved mayo (made with avocado oil)
  • 2 Tbsp dijon or brown mustard
  • 1-2 cups frozen peas (thawed)
  • 1 yellow onion, diced
  • 1-1½ cup sliced mushrooms
  • 1 inch of fresh ginger, grated
  • ½-¾ cup canned full-fat coconut milk
  • 3 Tbsp tapioca flour
  • 1-2 Tbsp avocado or coconut oil, for sautéing
  • ½ tsp salt (I use Redmond’s Real Salt)
  • ¼ tsp pepper
  • 1 tsp garlic powder
  • ½ tsp paprika
  • ¼ tsp red pepper flakes
  • 1-2 cups grated parmesan cheese (or cheese of choice)
  • chopped chives, garnish



  1. Preheat oven to 400 degrees.
  2. Cook the spaghetti squash.  Carefully slice squash in half lengthwise.  Remove the seeds, drizzle with a little olive oil and season with salt and pepper.  Place in glass casserole pan, face side down.  Add a small amount of water to the pan.  Bake for about 40 minutes.  Check doneness by poking with a fork.  Remove from oven and allow to cool.
  3. Using a fork, remove the squash from the shells with long strokes to create strands.  You can do this into a separate bowl or directly back into the casserole pan (making sure there is no remaining water and that your pan is sprayed or greased).
  4. In a large mixing bowl, combine the tuna, mayo, mustard, green chilis, grated ginger, garlic powder, half of the salt and pepper.  Mix and set aside.
  5. Heat the oil in a skillet over medium-high heat.  Add in the onions, and sauté for 2-3 minutes.  Add the mushrooms and ginger and sauté for an additional 2-3 minutes.
  6. Add the coconut milk, flour and spices to the skillet.  Whisk together with the onions and mushrooms.  Allow this to cook so the sauce can thicken.
  7. Add sauce in with the tuna mixture.  Stir to combine.
  8. If spaghetti squash is in a bowl, add it to the prepared casserole pan.  Layer the peas over the top of the squash.
  9. Pour the tuna and sauce mixture over the squash and peas.  Spread evenly over entire pan.
  10. Lastly, spread your cheese over the top and sprinkle with a little extra paprika.
  11. Bake for approximately 25-30 minutes or when casserole is bubbly and warmed through.  I made mine in the morning and put it in the fridge until evening.  In this case, it will take longer to bake than if your ingredients are still somewhat warm.
  12. Allow to sit briefly before cutting.