This Swiss cheese tuna casserole is a gourmet twist on the traditional dish. With rich albacore tuna, creamy Swiss cheese, tender mushrooms, and a crispy topping of French fried onions, it’s a hearty and satisfying meal that feels elevated yet comforting. Sweet peas balance the savory flavors, while the addition of hard-boiled eggs provides an unexpected protein boost. This casserole is creamy, flavorful, and perfect for weeknight dinners or potlucks.
Ingredients for Swiss Cheese Tuna Casserole
- 1 package button mushrooms, 8 oz (225 grams)
- 1 onion, diced small
- Worcestershire sauce, to taste
- 3 tablespoons butter (45 grams)
- 4 packages albacore tuna packed in water (2.5 oz each) (70 grams each, total 280 grams)
- 2 cups frozen petite peas (300 grams)
- 2 cans cream of mushroom soup (10.5 oz each) (300 grams each)
- Milk, enough to fill 2 soup cans (600 milliliters)
- 8 slices Swiss cheese (200 grams)
- 1 can French’s French fried onions, 6 oz (170 grams, enough to cover the top of the casserole)
- 1 package wide egg noodles (12 oz or 340 grams)
- Your favorite seasonings, to taste
- 3 hard-boiled eggs, diced
How to Make Swiss Cheese Tuna Casserole
Sauté the vegetables
Slice the mushrooms and dice the onion. Sauté them in butter over medium heat until softened.
Add Worcestershire sauce
Stir in Worcestershire sauce, adding generously for extra flavor. Continue to sauté, stirring frequently, until the vegetables are fully cooked.
Prepare the eggs and noodles
While the vegetables cook, boil the eggs and prepare the egg noodles according to the package instructions. Cook the noodles to al dente to prevent them from becoming mushy in the oven.
Make the sauce
Once the mushrooms and onions are done, add the tuna and your favorite seasonings to the skillet. Cook on low for a couple of minutes while stirring. In the same skillet, add the cream of mushroom soup and milk. Stir over low heat until the mixture is smooth and well combined.
Combine with noodles
Drain the cooked noodles and return them to the pot. Add the tuna mixture and stir until the noodles are fully coated.
Add eggs and peas
Dice the hard-boiled eggs using an egg slicer and add them to the noodle mixture. Stir in the peas and adjust seasoning as needed.
Transfer to a baking dish
Pour the mixture into a 9×13-inch (23×33 centimeters) baking dish, spreading it evenly.
Top with Swiss cheese
Layer the Swiss cheese slices over the casserole.
Bake the casserole
Cover the dish tightly with aluminum foil and bake in a preheated oven at 350°F (175°C) for 30-45 minutes, or until bubbly and the cheese is melted.
Add the crispy topping
Remove the foil and sprinkle the French fried onions over the top. Return the casserole to the oven and bake for an additional 10 minutes, or until the onions are golden brown.
Cool before serving
Let the casserole cool for a few minutes before serving—it will be very hot!
Why You’ll Love This Recipe
This Swiss cheese tuna casserole elevates the classic dish with rich and creamy flavors. The tender mushrooms and sweet peas add layers of texture, while the crispy onion topping provides the perfect crunch. The hard-boiled eggs are a surprising addition that adds even more protein, making this casserole a well-rounded and satisfying meal.
This Swiss cheese tuna casserole is a crowd-pleaser that’s easy to prepare and packed with flavor. Whether you serve it for a family dinner or take it to a potluck, it’s sure to impress. The balance of creamy, savory, and crispy elements creates a dish that feels indulgent yet comforting. Customize it with your favorite seasonings or cheeses, and enjoy a meal that’s destined to become a household favorite!
