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Tuna and Zucchini Noodle Casserole
with mixed greens salad

Active: 50 Total: 70

We always get requests from our community for more casseroles, and it doesn't get more classic than this paleo-friendly twist on tuna noodle casserole.
Smarts: Be sure to take your time when cooking the mushrooms and onions - the longer they cook, the more flavor they will develop.



Tuna and Zucchini Noodle Casserole:
  • Onions, medium - 1/2 , diced
  • Mushrooms, any button - 8 oz , chopped (look for pre-chopped to save time)
  • Zucchini - 12 oz , spiralized or peeled into ribbons
  • Peas, frozen or canned - 1 1/2 cups
  • Tuna, canned (5 oz / 142 g) - 2 cans , drained (look for Spanish or Italian varieties packed in olive oil )
  • Butter - 3 Tbsp
  • Arrowroot powder - 1 tsp
  • Salt - 1/2 tsp
  • Black pepper - 1/4 tsp
  • Stock, any type - 1 1/2 cups
  • Lemon zest - 1 tsp
Mixed Greens Salad:
  • Vinegar, balsamic - 1 Tbsp
  • Mustard, Dijon - 1 tsp
  • Maple syrup - 1/2 tsp
  • Oil, olive - 2 Tbsp
  • Mixed greens - 5 oz


  1. Onions - Prep as directed. (Can be done up to 5 days ahead)

  2. Mushrooms (if not pre-chopped) - Prep as directed. (Can be done up to 3 days ahead)

  3. Zucchini - Turn zucchini into 'noodles' with a spiralizer, peel off strips with a peeler, or slice into cubes. (Can be done 1 day ahead)

  4. Peas - Defrost if using frozen. Drain if using canned.

  5. Tuna - Drain cans of tuna.

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  1. Heat oven to 400F / 204C.

  2. Spray a square baker with nonstick cooking spray or brush with some oil. (Note: a square baker works well for 4 servings so adjust if customizing. For any number of servings, you can use any size or shape of baking dish as long as it will comfortably hold all of the casserole.)

  3. Melt butter in a large saucepan or Dutch oven over medium heat. When butter is melted, add mushrooms and onions and cook until deep golden brown and very tender, 9 to 12 minutes. 

  4. Sprinkle arrowroot powder, salt, and pepper over mushroom-onion mixture and stir until no dry spots remain. 

  5. Slowly pour stock over top while whisking. Bring to a simmer. Simmer until sauce thickens slightly, 4 to 5 minutes.

  6. Remove sauce from heat and gently fold in lemon zest, zucchini noodles, peas, and tuna.

  7. Transfer into prepared baking dish.

  8. Bake until sauce is bubbling and zucchini is tender, ~ 15 minutes. (Note: If you'd like to get the top crisp and golden, turn on the broiler in the last few minutes.) 

  9. While casserole bakes, in a large mixing bowl whisk together vinegar, mustard, maple syrup, and olive oil. Add greens on top, but wait to toss until just before serving.

  10. Season the top of the salad with some black pepper if you'd like.

  11. Serve casserole with salad on the side. Enjoy!



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