Step 1

Preheat oven to 400°F and grease an 8x8-inch baking dish with nonstick spray. Set aside.

Step 2

Boil noodles 2 minutes less than package directions call for. Drain and rinse. Set aside.

Step 3

In a large skillet over medium-high heat, melt 1 tablespoon butter. Add onion and celery and cook until soft, 5-7 minutes.

Step 4

In a large bowl, stir together noodles, onions and celery, peas, soup, milk, 1 cup cheese, tuna, and parsley. Spread into prepared baking dish.

Step 5

In a small bowl, stir together breadcrumbs, melted butter, and 1/2 cup cheddar cheese.

Step 6

Sprinkle breadcrumb mixture evenly over casserole and bake until bubbly and golden brown, about 20 minutes. Let rest 5 minutes before serving and garnish with fresh parsley, if desired. Enjoy!