Preheat oven to 350°F.

Spray a 9”x13” casserole dish with nonstick baking spray; set pan aside.

Cook egg noodles to al dente according to package instructions; drain cooked noodles and set aside.

Using a large, deep skillet, add butter and place over medium heat. Once butter has melted, sprinkle flour into pan; stir until well combined.

Add diced onions and celery; stir until well combined. Cook, stirring often, for 2-3 minutes.

Add garlic; continue cooking, stirring often, for 1 more minute.

Add chicken broth, milk, parsley, salt and black pepper; stir until well combined. Let mixture simmer over medium heat for 4-5 minutes.

Remove skillet from heat and add cheese, tuna, peas, broccoli and cooked egg noodles (from above); stir until well combined. Transfer mixture into prepared casserole dish.

Using a small bowl, combine the panko breadcrumbs, melted butter, grated Parmesan and dried parsley. Spread mixture evenly on top of casserole dish.

Bake for 20-25 minutes, or until topping turns golden brown.