# What you need:
→ Pasta
01 - 12 oz wide egg noodles
→ Sauce
02 - 2 tablespoons unsalted butter
03 - 1 small yellow onion, finely chopped
04 - 2 cloves garlic, minced
05 - 3 tablespoons all-purpose flour
06 - 2 cups whole milk
07 - 1 cup low-sodium chicken or vegetable broth
08 - 1/2 cup sour cream
09 - 1/2 teaspoon salt
10 - 1/2 teaspoon ground black pepper
11 - 1/2 teaspoon dried thyme
12 - 1/2 teaspoon dried parsley
→ Filling
13 - 2 cans (5 oz each) solid white tuna in water, drained and flaked
14 - 1 cup frozen peas, thawed
15 - 1 cup sliced white mushrooms (optional)
16 - 1 cup shredded cheddar cheese
→ Topping
17 - 1 1/2 cups store-bought crispy fried onions
# Steps to follow:
01 - Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish.
02 - Boil salted water in a large pot. Cook egg noodles until al dente, then drain and set aside.
03 - Melt butter in a large skillet over medium heat. Add chopped onion and sauté for 3 minutes until softened. Add minced garlic and cook for 1 minute.
04 - Sprinkle flour over the onion mixture and stir constantly for 1 minute to cook the flour.
05 - Gradually whisk in milk and broth. Cook while whisking until sauce thickens, about 3 to 4 minutes.
06 - Remove from heat. Stir in sour cream, salt, black pepper, thyme, and parsley.
07 - Add drained tuna, peas, mushrooms if using, and shredded cheddar cheese to the sauce. Stir until evenly combined.
08 - Gently fold cooked noodles into the sauce mixture until thoroughly mixed.
09 - Transfer the combined mixture into the prepared baking dish and spread evenly.
10 - Evenly sprinkle crispy fried onions over the casserole's surface.
11 - Bake uncovered for 25 to 30 minutes until the casserole bubbles and the onion topping turns golden brown.
12 - Allow casserole to rest for 5 minutes before serving to set.
