Preheat your oven to 375°F (190°C) and grease a baking dish with cooking spray.
Cook the egg noodles according to the package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the cooked noodles, drained tuna, cream of mushroom soup, frozen peas, shredded cheddar cheese, milk, and any optional ingredients.
Season the mixture with salt and pepper to taste, then gently stir until everything is evenly combined.
Transfer the mixture to the prepared baking dish, spreading it out evenly.
Sprinkle breadcrumbs over the top of the casserole for a crunchy topping.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbling and the breadcrumbs are golden brown.
Once done, remove from the oven and let it cool slightly before serving.