Preheat oven to 350 F and cook egg noodles according to package instructions.
In large bowl, mix egg noodles, peas, tuna, soup, milk, 1 1/4 cups cheddar cheese, celery salt, pepper and 2 tablespoons parsley.
Spray 9-by-13-inch casserole dish with nonstick cooking spray and add tuna mixture. Cover with aluminum foil and bake 20 minutes until hot and bubbly.
While casserole is baking, mix breadcrumbs and melted butter. Remove casserole from oven and top with breadcrumb mixture and remaining cheddar cheese.
Bake, uncovered, 5-10 minutes, until breadcrumbs are golden brown and cheese on top is melted. Sprinkle with Parmesan cheese and additional parsley, if desired, before serving.