Low FODMAP Tuna Casserole Recipe

This creamy, crunchy Low FODMAP Tuna Casserole is made with gluten-free pasta, savoury canned tuna, and a rich homemade cheese sauce, ready in 40 minutes. Watching the golden breadcrumb topping crisp up while the sauce bubbles underneath is purely satisfying. I finally found a way to enjoy this comfort classic without the tummy trouble.

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Why This Classic Works

Tuna casserole is the ultimate comfort food, but the traditional version relies heavily on condensed soups that are full of garlic and onion. I realised that making a quick béchamel sauce from scratch takes only five minutes and gives you complete control over the ingredients. Using garlic-infused oil provides that essential savoury depth without triggering any symptoms.

The secret to this version is using sharp cheddar cheese and a splash of Dijon mustard to mimic the tanginess you usually get from processed ingredients. I was surprised to find that the homemade sauce actually tastes much fresher and creamier than the canned stuff ever did. It proves that eating for gut health doesn’t mean eating bland food.

Low FODMAP Tuna Casserole Ingredients

• 12 oz (340g) gluten-free pasta (fusilli or penne works best)
• 2 cans (5 oz each) tuna in water, drained well
• 4 tbsp unsalted butter, divided
• 3 tbsp gluten-free all-purpose flour
• 2 cups lactose-free whole milk
• 1.5 cups sharp cheddar cheese, shredded
• 1/2 cup frozen peas (safe serving size) or chopped green beans
• 2 tbsp garlic-infused olive oil
• 1/2 cup gluten-free breadcrumbs or crushed cornflakes
• 1/4 cup green onion tops (green parts only), chopped
• 1 tsp Dijon mustard
• Salt and black pepper to taste

How To Make Low FODMAP Tuna Casserole

1. Boil the Pasta: Preheat your oven to 375°F (190°C). Cook the gluten-free pasta in a large pot of salted boiling water for 2 minutes less than the package instructions, then drain and set aside.
2. Make the Roux: In a large saucepan over medium heat, melt 3 tablespoons of butter with the garlic-infused oil. Whisk in the gluten-free flour and cook for 1 minute until bubbly but not browned.
3. Create the Sauce: Slowly whisk in the lactose-free milk to prevent lumps. Simmer for 3-4 minutes until the sauce thickens enough to coat the back of a spoon, then remove from heat and stir in the mustard, cheddar cheese, salt, and pepper until melted.
4. Combine Ingredients: Add the drained tuna, peas, green onion tops, and cooked pasta to the cheese sauce. Stir gently until everything is evenly coated, then transfer the mixture to a 9×13 inch baking dish.
5. Bake the Casserole: Melt the remaining 1 tablespoon of butter and mix it with the gluten-free breadcrumbs. Sprinkle this topping over the casserole and bake for 20-25 minutes until the sauce is bubbly and the top is golden brown.

Recipe Tips

• Undercook the pasta: Gluten-free pasta can turn to mush quickly. Boiling it for a few minutes less than usual ensures it stays firm after baking in the sauce.
• Check your tuna labels: Some canned tuna brands include vegetable broth containing onion or garlic. Always choose tuna packed in plain water or oil.
• Shred cheese yourself: Pre-shredded cheese often contains anti-caking agents that can be high FODMAP or just grainy. Grating a block of sharp cheddar yields the smoothest sauce.
• Manage the peas: Green peas are safe in small servings (about 1 tablespoon per person). If you are very sensitive, swap them for chopped carrots or extra green beans.

What To Serve With Tuna Casserole

A crisp green salad with a simple maple-mustard vinaigrette cuts through the richness of the creamy sauce perfectly. You could also serve this with steamed broccoli florets or roasted carrots to add more colour and nutrition to your dinner plate.

How To Store

Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the microwave or oven, adding a splash of water if the pasta has absorbed too much sauce. Freezing is possible, but gluten-free pasta tends to change texture significantly, so fresh is best.

FAQs

• Can I use almond milk instead of lactose-free milk?
  Yes, unsweetened almond milk works well, though the sauce will be slightly less rich than with cow’s milk.
• Is garlic-infused oil really safe?
  Yes, FODMAPs are water-soluble but not oil-soluble. Using oil that has been infused with garlic and then strained provides the flavour without the fructans.
• What breadcrumbs are safe?
  Look for specifically labelled gluten-free breadcrumbs or simply crush up plain gluten-free cornflakes for a great crunch.
• Can I make this ahead of time?
  You can assemble the casserole up to the baking step and keep it in the fridge for 24 hours. Add the breadcrumbs right before baking.

Nutrition

• Calories: 485 kcal
• Total Fat: 22g
• Saturated Fat: 12g
• Cholesterol: 65mg
• Sodium: 580mg
• Total Carbohydrate: 45g
• Protein: 28g

Try More Recipes:

• Easy Low FODMAP Turkey Meatballs Recipe
• Low FODMAP Roasted Sweet Potatoes Recipe
• Crispy Low FODMAP Sweet Potato Fries Recipe