Tuna Noodle Casserole Onion

Featured in: Warm Family Dinners

This classic dish combines tender egg noodles with flavorful tuna, peas, and a creamy sauce infused with butter, garlic, and Dijon mustard. The mix is topped with crispy fried onions, creating a delightful contrast of textures. Baked until bubbly and golden, this comforting meal suits family dinners and cozy gatherings. Optional mushrooms add earthiness, while seasonings like thyme enhance the savory depth. Easy to prepare and satisfying, it can be paired with fresh greens or a crisp white wine for a complete dining experience.

Updated on Thu, 20 Nov 2025 15:38:00 GMT
Golden-crusted Homemade Tuna Noodle Casserole, bubbly and cheesy, ready to be served hot. Save
Golden-crusted Homemade Tuna Noodle Casserole, bubbly and cheesy, ready to be served hot. | amberladle.com

A comforting, creamy classic featuring tender noodles, savory tuna, and a golden, crunchy onion topping — perfect for family dinners or cozy gatherings.

I first made this casserole on a chilly weekend, and the aroma that filled our kitchen instantly brought everyone to the table. It's become a go-to comfort meal we look forward to making together.

Ingredients

  • Pasta: 340 g (12 oz) egg noodles
  • Seafood: 2 cans (each 170 g/6 oz) tuna in water, drained
  • Vegetables: 1 cup frozen peas, thawed, 1 small onion, finely chopped, 2 cloves garlic, minced, 1 cup sliced button mushrooms (optional)
  • Sauce: 2 tablespoons unsalted butter, 2 tablespoons all-purpose flour, 2 cups whole milk, 120 ml (½ cup) sour cream, 1 teaspoon Dijon mustard, ½ teaspoon salt, ½ teaspoon black pepper, ½ teaspoon dried thyme
  • Cheese: 1 cup (about 100 g) shredded cheddar cheese
  • Topping: 1 cup crispy fried onions (store-bought or homemade)

Instructions

Prepare Baking Dish:
Preheat oven to 190°C (375°F). Lightly grease a 23 x 33 cm (9 x 13 inch) baking dish.
Cook Noodles:
Cook egg noodles according to package directions until al dente. Drain and set aside.
Make Vegetable Base:
In a large skillet over medium heat, melt butter. Add chopped onion and mushrooms and sauté 4–5 minutes until softened. Add garlic and cook 1 minute more.
Prepare Sauce:
Sprinkle flour over vegetables and stir for 1 minute. Gradually whisk in milk, stirring constantly. Cook until sauce thickens, about 3–4 minutes.
Add Flavor and Combine:
Stir in sour cream, Dijon mustard, salt, pepper, and thyme. Remove from heat.
Combine Ingredients:
Add drained tuna, peas, cheddar cheese, and cooked noodles to the sauce. Mix gently until combined.
Assemble and Top:
Spoon mixture into prepared baking dish. Sprinkle crispy fried onions evenly over the top.
Bake:
Bake uncovered for 25–30 minutes, or until bubbly and golden.
Rest and Serve:
Let stand 5 minutes before serving.
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| amberladle.com

Gathering the family for a hearty serving always sparks laughter and conversation around our dinner table. This casserole is one of those cozy meals that brings everyone together.

Required Tools

Large pot, large skillet, whisk, baking dish (23 x 33 cm/9 x 13 inch), mixing utensils

Allergen Information

Contains: Milk (butter, cheese, milk, sour cream), Wheat (noodles, flour), Fish (tuna), Eggs (egg noodles), and possibly Gluten (noodles, crispy onions). Always verify packaging for detailed allergen statements.

Nutritional Information

Per serving: Calories 430, Total Fat 17 g, Carbohydrates 44 g, Protein 25 g

A close-up of creamy, flavorful Homemade Tuna Noodle Casserole with a crispy onion topping. Save
A close-up of creamy, flavorful Homemade Tuna Noodle Casserole with a crispy onion topping. | amberladle.com

Serve this casserole hot and let everyone enjoy that crunchy topping! Leftovers reheat beautifully and taste even better the next day.

Recipe FAQs

What type of noodles work best?

Egg noodles are ideal for their tender texture and ability to hold the creamy sauce well.

Can I substitute the sour cream?

Greek yogurt is a great alternative, adding tanginess while maintaining creaminess.

How do I achieve a crispy onion topping?

Use store-bought crispy fried onions or prepare homemade ones by frying thinly sliced onions until golden.

Is it possible to add vegetables?

Yes, peas are included and optional mushrooms can be sautéed for added flavor and texture.

What spices enhance the flavor?

Dried thyme and Dijon mustard provide subtle herbal and tangy notes that complement the creamy base.

How long should the dish bake?

Bake uncovered for 25–30 minutes at 190°C (375°F) until bubbly and golden on top.

Tuna Noodle Casserole Onion

Comforting casserole with tender noodles, tuna, peas, and crunchy onion topping baked to golden perfection.

Prep time
20 min
Cook time
30 min
Overall time
50 min
Created by Rachel Hayes


Skill required Easy

Cuisine American

Makes 6 Serving size

Diet preferences None specified

What you need

Pasta

01 12 oz egg noodles

Seafood

01 2 cans (6 oz each) tuna in water, drained

Vegetables

01 1 cup frozen peas, thawed
02 1 small onion, finely chopped
03 2 cloves garlic, minced
04 1 cup sliced button mushrooms (optional)

Sauce

01 2 tablespoons unsalted butter
02 2 tablespoons all-purpose flour
03 2 cups whole milk
04 ½ cup sour cream
05 1 teaspoon Dijon mustard
06 ½ teaspoon salt
07 ½ teaspoon black pepper
08 ½ teaspoon dried thyme

Cheese

01 1 cup shredded cheddar cheese

Topping

01 1 cup crispy fried onions

How to make it

Step 01

Preheat Oven and Prepare Dish: Preheat oven to 375°F. Lightly grease a 9 x 13 inch baking dish.

Step 02

Cook Noodles: Cook egg noodles according to package instructions until al dente. Drain and set aside.

Step 03

Sauté Vegetables: In a large skillet over medium heat, melt butter. Add chopped onion and mushrooms; sauté for 4 to 5 minutes until softened. Add garlic and cook for 1 additional minute.

Step 04

Make Sauce: Sprinkle flour over vegetables and stir continuously for 1 minute. Gradually whisk in milk, stirring constantly, and cook until sauce thickens, approximately 3 to 4 minutes.

Step 05

Season and Combine Sauce: Remove skillet from heat and stir in sour cream, Dijon mustard, salt, pepper, and dried thyme.

Step 06

Fold in Main Ingredients: Add drained tuna, thawed peas, shredded cheddar cheese, and cooked noodles to the sauce. Gently mix until evenly combined.

Step 07

Assemble Casserole: Transfer mixture to the prepared baking dish.

Step 08

Add Topping: Sprinkle crispy fried onions evenly over the top.

Step 09

Bake: Bake uncovered for 25 to 30 minutes, until bubbly and golden brown.

Step 10

Rest Before Serving: Allow casserole to rest for 5 minutes before serving.

Equipment needed

  • Large pot
  • Large skillet
  • Whisk
  • 9 x 13 inch baking dish
  • Mixing utensils

Allergy info

Always review ingredients for allergens. Talk to your healthcare provider if you're unsure.
  • Contains milk (butter, cheese, sour cream), wheat (noodles, flour), fish (tuna), eggs (egg noodles), and possibly gluten (noodles, crispy onions).

Nutrition details (each serving)

Nutritional details are for reference and aren't a substitute for healthcare guidance.
  • Calorie Count: 430
  • Fat content: 17 g
  • Carbohydrate: 44 g
  • Protein amount: 25 g