Combine all ingredients for the topping; set aside.
Dice onion and celery.
Preheat oven to 425°F/220⁰C.
Cook egg noodles al dente according to package directions. Drain, add a drizzle of olive oil to noodles, give a stir, and set aside.
Sauté onion and celery in butter over medium heat for 5 minutes, or until onion is translucent.
Combine onion mixture with cooked noodles, peas, soup, milk, cheese, tuna and parsley.
Pour into 9 x 13 Rectangle Stone, and sprinkle with breadcrumb topping.
Bake for 15-18minutes, or until topping is nicely browned and casserole is bubbling. Serve immediately.
Notes
Tuna casserole freezes beautifully! To freeze, let cool completely. I like to cut into individual portions, then place in a freezer safe container or bag, and freeze for up to three months.Thaw individual servings in the refrigerator for 24 hours, then reheat in your Air Fryer or oven at 350°F/175⁰C for 15 minutes, or until heated through.