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Best Tuna Noodle Casserole from Scratch

This creamy casserole is as close to comfort food as you can get with no canned ingredients! It does take some effort to make, but it's worth it. You can also change this recipe into an amazing turkey tetrazzini casserole by swapping out the tuna.
Print Recipe
Prep Time 20 minutes
Cook Time 50 minutes
Total Time 1 hour 10 minutes
Course lunch/dinner
Cuisine asian
Servings 4 people
Calories 2833.8 kcal

Equipment

  • 1 Ovenproof Skillet For baking tuna steaks.
  • 1 8x12-inch Casserole Dish Essential for baking the final casserole.
  • 1 Large Saucepan For boiling pasta and preparing the sauce.
  • 1 Whisk Crucial for smooth sauce consistency.
  • 1 Chef's Knife and Cutting Board For dicing onions and slicing mushrooms.

Ingredients
  

Main

  • 2 5 ounce tuna steaks
  • 8 ounces fettuccine noodles
  • 6 tablespoons butter divided
  • 1 medium onion diced
  • 6 ounces sliced portobello mushrooms
  • ¼ cup flour
  • 2 ¾ cups milk
  • 1 teaspoon chicken bouillon concentrate such as Better than Bouillon®
  • ½ teaspoon adobo seasoning
  • ¼ teaspoon black pepper
  • ¼ cup grated Parmesan cheese
  • 4 slices bread torn into small pieces

Instructions
 

  • Preheat the oven to 350 degrees F (175 degrees C). Lightly oil an ovenproof skillet and an 8x12-inch casserole dish.
  • Place tuna in the prepared skillet and bake in the preheated oven until fish flakes easily with a fork, 8 to 10 minutes.
  • Fill a large saucepan with lightly salted water and bring to a rolling boil. Cook fettuccine at a boil until tender yet firm to the bite, about 8 minutes. Drain and set aside.
  • Remove tuna from the oven; leave oven on.
  • Meanwhile, melt 3 tablespoons butter in a saucepan over medium heat. Cook onion and mushrooms until softened, stirring occasionally, 5 to 7 minutes. Stir in flour until blended. Add milk, bouillon concentrate, adobo seasoning, and black pepper. Cook, stirring constantly, until mixture is slightly thickened, about 5 minutes more. Remove sauce from heat and stir in Parmesan cheese.
  • Place remaining butter in a medium-sized microwave-safe bowl and heat in the microwave until melted, about 30 seconds. Stir bread crumbs into melted butter and set aside.
  • Add cooked fettuccine and flaked tuna to the cheese sauce and toss to combine. Transfer noodle mixture to the prepared casserole dish and top with torn bread.
  • Bake in the hot oven until golden brown, about 20 minutes.

Notes

This scratch-made casserole offers superior flavor. For the tuna, aim for just cooked through; overcooking will result in dry fish. The key to a silky sauce is constant stirring when adding flour and milk to prevent lumps. A pinch of freshly grated nutmeg can elevate the béchamel base. For the topping, ensure the bread is torn, not finely crumbed, for varied texture. If you want an extra crispy topping, you can lightly toast the buttered bread pieces in a dry skillet before sprinkling them over the casserole. Garnish with fresh chopped parsley or chives for a pop of color and freshness. Consider adding frozen peas or corn to the noodle mixture for added vegetables and visual appeal.