Preheat the oven to 375°F and grease a 9x13 baking dish. Cook the egg noodles in a large pot of boiling water until al dente, then drain them well.
In a mixing bowl, stir together the cream of mushroom soup, milk, salt, and black pepper until smooth. Add the drained tuna, frozen peas, and half of the shredded cheddar cheese.
Fold the cooked noodles into the bowl and mix until the noodles are evenly coated with the sauce.
Spread the mixture into the prepared baking dish and sprinkle the remaining shredded cheddar cheese over the top.
Combine the panko breadcrumbs with the melted butter in a small bowl, then scatter this mixture evenly across the surface of the casserole.
Bake for 20 to 25 minutes until the topping turns golden and the edges bubble.