Mackeral Caserole

Tuna casserole was a favourite comfort food for me before I went keto, loved for its tastiness and for how easy it was to whip one up. I wanted to make something similar for my keto diet, but one that used a healthier, yet still inexpensive fish, and of course the pasta and peas had to go. Mackerel was the perfect fit. It's relatively neutral tasting like tuna, can be bough cheaply at dollar stores, and it's a small fish so it doesn't have the mercury issues that a larger fish like tuna has.

As for veggies, most recipes use cauliflower or zucchini to sub for pasta, but I wanted something different so I went with cabbage. And since the cabbage was already green, I went with diced red pepper to give it some colour and additional nutrition. And as with all my recipes, I use full fat versions of all the dairy products. Lastly, I went with crushed up spicy pork rinds to replace bread crumbs (or potato chips depending on what you grew up with) as the topping. Definitely use spicy ones as it adds a nice contrasting flavour on top of the creaminess of the dish.

Holy Mackerel Keto Casserole Recipe


  • 2 tablespoons unsalted butter
  • 1 tablespoon extra virgin olive oil
  • 4 cups green cabbage (sliced into noodles)
  • 1 large can of mackerel, chopped (remove bones and freeze for making bone broth if desired)
  • 2 cloves garlic, minced
  • ½ cup yellow onion, sliced
  • ½ cup red bell pepper, diced
  • ½ cup white mushrooms, sliced
  • 1/2 teaspoon celery salt
  • ¼ teaspoon ground black pepper
  • ¾ teaspoon ground mustard
  • ½ cup sour cream
  • ¼ cup heavy cream
  • 2 tablespoons mayonnaise
  • ½ cup mozzarella cheese, shredded
  • ½ cup cheddar cheese, shredded
  • 14g of spicy pork rinds, crushed
  • 3 tablespoons fresh parsley, chopped (for garnish)
  • Salt and pepper (to taste)


  1. Preheat oven to 350F.
  2. Heat the olive oil and butter in an extra large skillet over medium heat.
  3. Once heated, add the cabbage, onion, and red pepper to pan and sauce until softened.
  4. Add garlic and mushrooms and continue to sauce until cabbage is the softened with a little crunch (not mushy).
  5. Add in celery salt, pepper, and ground mustard and cook for 1 minute.
  6. Add heavy cream, sour cream, and mayonnaise and allow sauce to thicken.
  7. Once the sauce has thickened, stir in mackerel and cook until heated through.
  8. If your skillet is overproof, sprinkle shredded cheese over everything. If it's not oven proof, transfer mixture over to a 2-quart casserole dish first then put in the oven for 20 minutes.
  9. After 20 minutes, take it out and add crushed pork rinds on top and put back in the oven for another 5 minutes.
  10. Allow to cool for 8-10 minutes to set. Sprinkle fresh parsley on top and serve. Makes 4 servings.

If you make this dish, let me know how it goes in the comments. I'm always interested to hear what substitutions people make to recipes too. Or if you share pics on Instagram, please tag me in the photos. :)