# What You'll Need:
→ Pasta and Fish
01 - 12 oz egg noodles
02 - 2 cans (5 oz each) solid white tuna in water, drained
→ Vegetables
03 - 1 cup frozen peas, thawed
04 - 1 cup cremini or white mushrooms, sliced
05 - 1 small yellow onion, finely chopped
06 - 1 cup celery, diced
07 - 2 cloves garlic, minced
→ Sauce
08 - 3 tbsp unsalted butter
09 - 3 tbsp all-purpose flour
10 - 2 cups low-sodium chicken or vegetable broth
11 - 1 cup whole milk
12 - 1/2 cup sour cream
13 - 1/2 tsp kosher salt
14 - 1/2 tsp freshly ground black pepper
15 - 1/2 tsp Dijon mustard
→ Topping
16 - 3/4 cup panko breadcrumbs
17 - 1/2 cup grated parmesan cheese
18 - 2 tbsp unsalted butter, melted
19 - 2 tbsp chopped fresh parsley (optional)
# How To Make It:
01 - Preheat the oven to 400°F. Lightly grease a 9x13-inch baking dish.
02 - Boil egg noodles in salted water until al dente. Drain and set aside.
03 - Melt butter in a large skillet over medium heat. Add onion and celery; sauté for 3 minutes. Add mushrooms and cook an additional 4 minutes until softened. Stir in garlic and cook 1 minute more.
04 - Sprinkle flour over vegetables, stirring to coat. Gradually whisk in broth, then add milk and bring to simmer. Cook, stirring, until thickened, about 3–4 minutes.
05 - Remove skillet from heat. Stir in sour cream, Dijon mustard, salt, and pepper until combined.
06 - Fold tuna, peas, and cooked noodles into the sauce mixture until evenly combined.
07 - Transfer mixture into the prepared baking dish.
08 - In a small bowl, combine panko breadcrumbs, parmesan cheese, and melted butter. Sprinkle evenly over casserole.
09 - Bake for 20 to 25 minutes until the topping is golden and the casserole is bubbling.
10 - Allow casserole to rest for 5 minutes. Sprinkle with parsley before serving.