Tasty Tuna Casserole with French Fried Onions

I didn’t grow up eating tuna casserole, but my husband did, and he requests it at least once a month. The first time I made it for him, I thought it seemed kind of bland—just noodles, canned tuna, and cream of mushroom soup. But then I added those crispy French fried onions on top, and everything changed.

Those crunchy onions aren’t just a topping—they’re what make this whole dish work. They add texture and flavor to what could otherwise be a pretty boring meal. Now I get why this recipe has been around forever. It’s easy to throw together on a busy weeknight, and my kids actually eat it without complaining.

What Kind of Tuna Should I Use?

For this casserole, you’ll want to use tuna packed in water rather than oil, since it has a milder flavor and won’t make your dish greasy. Both chunk light and solid white albacore tuna work great here, though chunk light is more budget-friendly and has a softer texture that blends nicely into the creamy sauce. The key is to drain your tuna really well – give those cans a good squeeze to get out as much liquid as possible, otherwise you’ll end up with a watery casserole. If you prefer, you can even use pouch tuna instead of canned, which tends to be a bit less messy and easier to drain.

Options for Substitutions

This classic casserole is pretty forgiving when it comes to swaps:

• Egg noodles: You can use any short pasta you have on hand – rotini, penne, or shells all work great. Just cook according to package directions before mixing into the casserole.
• Cream of mushroom soup: If you’re not a mushroom fan, try cream of chicken or cream of celery soup instead. You can also make a quick homemade version by mixing 2 cups of milk with 4 tablespoons of flour and butter, then seasoning to taste.
• Tuna: Canned chicken or salmon work as easy substitutes. You can also use leftover cooked chicken – just shred it up and add it in.
• Sour cream: Plain Greek yogurt or cottage cheese (blended smooth) can replace sour cream in equal amounts for a lighter option.
• Cheddar cheese: Any melty cheese works here – try Monterey Jack, Colby, or a Mexican blend if that’s what you have.
• French fried onions: Crushed potato chips, panko breadcrumbs mixed with melted butter, or even crushed crackers make a nice crunchy topping if you don’t have the onions.

Watch Out for These Mistakes While Baking

The biggest mistake you can make with tuna casserole is overcooking the egg noodles before they go into the oven – cook them just until they’re slightly underdone (about 2 minutes less than the package directions) since they’ll continue cooking in the casserole and you don’t want them turning mushy.

Make sure to drain your tuna really well by pressing it with paper towels or the back of a spoon, because excess water will make your casserole watery and prevent the creamy sauce from coating everything properly.

Don’t add those french fried onions at the beginning or they’ll get soggy – wait until the last 10 minutes of baking so they stay crispy and golden on top.

If your casserole seems too thick when mixing, add a splash of milk to loosen it up, and always let it rest for about 5 minutes after baking so the sauce can thicken and settle before serving.

What to Serve With Tuna Casserole?

Tuna casserole is a hearty meal on its own, but I love serving it with a simple side salad to balance out all that creamy goodness. A basic mixed greens salad with cherry tomatoes, cucumber, and a light vinaigrette works perfectly and adds some freshness to the plate. Steamed green beans or roasted broccoli are also great options if you want to add more veggies to the meal. For something a bit more filling, garlic bread or dinner rolls are perfect for rounding out the dinner, especially if you’re feeding hungry kids or guests.

Storage Instructions

Store: Leftover tuna casserole keeps really well in the fridge for up to 4 days. Just cover it tightly with foil or transfer it to an airtight container once it’s cooled down. The french fried onions might lose a bit of their crunch, but the casserole will still taste great.

Freeze: You can freeze this casserole for up to 2 months, but I’d recommend freezing it before adding the french fried onions on top. That way, you can add fresh ones when you reheat it and they’ll stay nice and crispy.

Reheat: Warm it up in the oven at 350°F covered with foil until heated through, about 20-25 minutes. If you want to crisp up the onions again, uncover it for the last 5 minutes. You can also reheat individual portions in the microwave for 2-3 minutes, stirring halfway through.

Preparation Time	10-15 minutes
Cooking Time	35-40 minutes
Total Time	45-55 minutes
Level of Difficulty	Easy

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 2700-3000
• Protein: 110-130 g
• Fat: 120-140 g
• Carbohydrates: 250-280 g

Ingredients

For the casserole:

• 12 oz wide egg noodles (cooked until al dente, about 6-7 minutes)
• 1 cup sour cream (room temperature for smoother mixing)
• 1/4 tsp onion powder
• 1.5 cups shredded cheddar cheese (medium or sharp, finely shredded)
• 2 cans tuna in water (drained thoroughly, pressing out excess liquid)
• 2 cans condensed cream of mushroom soup (I use Campbell’s)
• 1 cup frozen green peas
• 1/4 tsp black pepper (freshly ground preferred)

For the topping:

• 6 oz crispy fried onions (I use French’s, reserve half for garnish)

Step 1: Prepare the Oven and Cook the Pasta

• 12 oz wide egg noodles

Preheat your oven to 350°F and bring a large pot of salted water to a boil.

Once boiling, add the egg noodles and cook for 6-7 minutes until al dente—they should have a slight firmness when you bite them since they’ll continue cooking in the oven.

Drain the noodles thoroughly in a colander and return them to the pot; set aside.

Step 2: Build the Casserole Base

• cooked noodles from Step 1
• 2 cans tuna in water
• 2 cans condensed cream of mushroom soup
• 1 cup sour cream
• 1/4 tsp onion powder
• 1/4 tsp black pepper
• 1 cup frozen green peas

To the pot of cooked noodles, add the drained tuna, condensed cream of mushroom soup, sour cream at room temperature, onion powder, black pepper, and frozen green peas.

Mix everything together thoroughly until the ingredients are evenly distributed and the sauce coats all the noodles.

The room-temperature sour cream will blend smoothly without any lumps, creating a creamy, cohesive base.

Step 3: Assemble and Add Cheese

• casserole mixture from Step 2
• 1.5 cups shredded cheddar cheese

Spray a 9×13-inch baking dish with cooking spray or lightly grease it with butter.

Transfer the noodle mixture from the pot into the prepared baking dish, spreading it evenly.

Sprinkle the shredded cheddar cheese evenly over the top, making sure it covers most of the surface for even melting and browning.

Step 4: First Bake and Add Fried Onions

• 6 oz crispy fried onions

Bake the casserole uncovered for 25 minutes until the cheese is melted and the edges are bubbling slightly.

Remove the casserole from the oven and quickly distribute 3 oz of the crispy fried onions evenly over the top—I like to crush them slightly so they distribute more evenly and create a better texture.

Reserve the remaining 3 oz of onions for a fresh garnish after baking.

Step 5: Final Bake and Rest

• reserved crispy fried onions

Return the casserole to the oven for 10 more minutes until the fried onions on top turn golden brown and crispy.

Remove from the oven and let it rest for 5 minutes—this helps the casserole set slightly so it holds together better when served.

Top with the reserved crispy fried onions for a fresh crunch and garnish, then serve warm.