Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish.
Cook the egg noodles according to package instructions until al dente. Drain and set aside.
In a large mixing bowl, combine the cream of mushroom soup, milk, shredded cheddar cheese, drained tuna, and frozen peas. Season with salt and pepper to taste.
Add the cooked egg noodles to the mixture and gently fold until well combined.
Transfer the mixture to the prepared baking dish, spreading it out evenly.
In a small bowl, mix together the breadcrumbs and melted butter. Sprinkle this mixture evenly over the top of the casserole.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 10 minutes, or until the casserole is bubbly and the top is golden brown.
Let the casserole cool for a few minutes before serving. Enjoy!