A creamy baked tuna casserole prepared with tender egg noodles, albacore tuna, chopped vegetables, cheddar cheese, and a smooth cream of chicken sauce. The casserole is baked until set and lightly browned, with an optional brief broil for a deeper golden finish.
Prepare the creamy mixture. In a large mixing bowl, whisk together the 10 1/2 oz cream of chicken soup, 1/2 cup mayonnaise, and 1/4 cup milk until the mixture becomes smooth and evenly blended.
Incorporate the vegetables. Add the 1/2 cup chopped yellow onion and 1/2 cup chopped celery to the creamy base. Stir thoroughly so the vegetables are distributed uniformly throughout the mixture.
Add the tuna, noodles, and cheese. Gently fold in the 6 oz albacore tuna, followed by the 6 oz cooked egg noodles and 1/4 cup shredded cheddar cheese. Continue folding carefully until all ingredients are evenly incorporated, taking care not to break the noodles excessively.
Season the casserole mixture. Taste the prepared filling and add salt and black pepper according to preference. Stir gently once more to disperse the seasonings evenly.
Bake the casserole. Transfer the mixture to a casserole dish and spread it into an even layer. Bake in a preheated 375°F (190°C) oven for approximately 40–45 minutes, or until the casserole is set and the surface begins to brown.
For a more pronounced golden surface, place the casserole under the broiler during the final couple of minutes of cooking. Watch it closely during this stage to prevent the top from burning.