Remove the casserole from the oven and let it rest for about 5 minutes. This short rest helps it set up a bit so it scoops nicely. Serve warm, straight from the baking dish, and watch it disappear.
Variations & Tips
For families, this casserole is easy to tweak for different tastes. If you have kids who are picky about herbs, you can swap the Italian seasoning for just a pinch of garlic powder and a little salt and pepper. For extra creaminess, stir 2–3 tablespoons of softened cream cheese into the mayonnaise mixture. If you’d like more vegetables without adding carbs, fold in a handful of finely chopped cooked broccoli, spinach, or cauliflower rice with the tuna before topping with the cheese mixture. To make it a bit more filling while still staying relatively low carb, you can sprinkle cooked, crumbled bacon over the top before baking. For a slightly sharper flavor, use a blend of mild mozzarella and a little shredded cheddar or Swiss. If you need this recipe to be gluten-free, simply check that your canned tuna and dried seasoning blend are certified gluten-free; the base recipe itself doesn’t use flour or breadcrumbs. Food safety tips: always drain the tuna thoroughly and keep it refrigerated until you’re ready to assemble. Once baked, refrigerate leftovers within 2 hours in a covered container and eat within 3–4 days, reheating only the portion you plan to serve. Reheat in a 300°F (150°C) oven until hot in the center, or gently in the microwave, making sure it reaches a steaming temperature before serving.
