35-Minute One Pot Tuna Casserole

Weeknight dinners can feel like a juggling act. Between work, homework help, and everything else on my plate, I need meals that come together fast and don’t leave my kitchen looking like a disaster zone. That’s where one pot meals save the day. Everything cooks in a single dish, which means less time scrubbing pots and more time actually sitting down with my family.

Tuna casserole gets a bad rap, but I think people just haven’t had a good version. When you make it right, it’s creamy, comforting, and something my kids actually ask for. Plus, I always have the ingredients sitting in my pantry, so it’s perfect for those nights when I forgot to plan ahead.

This version takes about 30 minutes from start to finish. No precooking pasta in a separate pot, no fancy ingredients you have to hunt down at three different stores. Just simple, straightforward comfort food that actually tastes good.

What Kind of Tuna Should I Use?

For this casserole, solid white albacore tuna is your best bet since it has a firmer texture and milder flavor that holds up well during cooking. That said, if you prefer chunk light tuna or it’s what you have in your pantry, go ahead and use it – the casserole will still turn out great. When shopping, look for tuna packed in water rather than oil, as it works better with the creamy soup base and won’t make your casserole greasy. Make sure to drain your tuna really well before adding it to the pot, giving the can a good squeeze to get rid of excess liquid.

Options for Substitutions

This one pot wonder is easy to customize based on what you have in your pantry:

• Cream of mushroom soup: You can swap this with cream of chicken or cream of celery soup for a different flavor profile. If you want to make it from scratch, mix 1 cup of milk with 2 tablespoons flour and 1 cup sautéed mushrooms.
• Shell pasta or rotini: Any short pasta shape works here – try elbow macaroni, penne, or farfalle. Just keep the cooking time the same and check for doneness.
• Tuna: Canned salmon or even cooked chicken breast (shredded or diced) make great substitutes. You can also use chunk light tuna instead of albacore if that’s what you have on hand.
• Cheddar cheese: Feel free to use whatever melting cheese you prefer – mozzarella, Monterey Jack, or a cheese blend all work well in this casserole.
• Seasoned croutons: Regular breadcrumbs, panko, or even crushed crackers (like Ritz) give you that crunchy topping. Mix in a little melted butter and garlic powder if using plain breadcrumbs.
• Celery: Not a celery fan? Try diced bell peppers or leave it out entirely – the casserole will still turn out great.

Watch Out for These Mistakes While Cooking

The biggest mistake people make with one pot tuna casserole is adding the tuna too early in the cooking process, which causes it to break apart and become dry – wait until the pasta is fully cooked before gently folding in the drained tuna.

Another common error is not stirring the pasta frequently enough while it cooks, leading to uneven cooking and pasta sticking to the bottom of the pot, so give it a good stir every few minutes.

Make sure you’re using uncooked pasta as the recipe calls for, since pre-cooked pasta will turn mushy when simmered in the liquid, and keep an eye on the water level – if the pasta isn’t quite tender but the liquid has evaporated, add a splash more water to prevent burning.

Finally, add the crushed croutons right before serving rather than letting them sit in the hot casserole, which keeps them crunchy instead of soggy.

What to Serve With Tuna Casserole?

Tuna casserole is a hearty one-pot meal, so I like to keep the sides simple and fresh to balance out all that creamy goodness. A crisp green salad with a tangy vinaigrette is my go-to – it cuts through the richness of the cheese and cream of mushroom soup perfectly. Steamed green beans or roasted broccoli also work great on the side, adding some color and vegetables to your plate. If you want something a bit more filling, garlic bread or dinner rolls are perfect for soaking up any extra sauce left in your bowl.

Storage Instructions

Store: Keep any leftover tuna casserole in an airtight container in the fridge for up to 3 days. The pasta will soak up some of the sauce as it sits, so it might be a bit thicker when you go to reheat it. If it seems too dry, just stir in a splash of milk or water to loosen it up.

Freeze: This casserole freezes pretty well for up to 2 months. Let it cool completely, then transfer to a freezer-safe container. I’d skip adding the croutons on top before freezing since they’ll get soggy – just add fresh ones when you reheat.

Reheat: Warm it up in the microwave in 1-minute intervals, stirring in between, or heat it on the stovetop over medium-low heat with a little extra liquid if needed. You can also reheat it in the oven at 350°F covered with foil until heated through, about 20 minutes.

Preparation Time	10-15 minutes
Cooking Time	25-30 minutes
Total Time	35-45 minutes
Level of Difficulty	Easy

Estimated Nutrition

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

• Calories: 1250-1400
• Protein: 65-75 g
• Fat: 40-50 g
• Carbohydrates: 150-165 g

Ingredients

For the casserole:

• 1 tbsp butter (I use Kerrygold unsalted butter)
• 2 celery stalks (chopped into 1/4-inch pieces)
• 1.5 cups water
• 1/3 cup shredded cheddar cheese
• 1 cup uncooked medium shell pasta
• 2 cans (5 oz each) solid white albacore tuna (drained well to remove excess liquid)
• 1 can condensed cream of mushroom soup

For the topping:

• 1 cup seasoned croutons (crushed into bite-sized pieces for even distribution)
• 1/3 cup shredded cheddar cheese

Step 1: Build the Flavor Base with Aromatics

• 1 tbsp butter
• 2 celery stalks, chopped into 1/4-inch pieces
• 1 can condensed cream of mushroom soup
• 1.5 cups water

Melt the butter in a large pot or Dutch oven over medium heat.

Add the chopped celery and sauté for 4-5 minutes, stirring occasionally, until the celery softens and becomes translucent.

This develops a subtle sweetness in the celery that will enhance the overall dish.

Once softened, pour in the cream of mushroom soup and water, stirring well to combine and break up any lumps in the soup.

Increase heat to medium-high and bring the mixture to a gentle simmer, which should take about 2-3 minutes.

Step 2: Cook the Pasta Until Tender

• 1 cup uncooked medium shell pasta
• simmering mixture from Step 1

Add the uncooked shell pasta to the simmering mixture from Step 1 and stir well to prevent clumping.

Reduce heat to low, cover the pot with a lid, and cook for 10-12 minutes, stirring occasionally.

The pasta will absorb liquid and become tender, and the sauce will thicken naturally as it cooks.

Check the pasta at the 10-minute mark—it should be soft but still hold its shape.

Step 3: Fold in Tuna and Melt the Cheese

• 2 cans solid white albacore tuna, drained well
• 1/3 cup shredded cheddar cheese

Remove the pot from heat and gently fold in the well-drained tuna with a spatula, breaking it into bite-sized chunks as you combine it.

I find that draining the tuna thoroughly is key—excess liquid can make the casserole watery, so take the extra 30 seconds to press it in a strainer.

Add half of the shredded cheddar cheese (about 1/3 cup) and stir until the cheese melts completely into the warm pasta mixture, creating a creamy sauce.

Taste and adjust seasoning if needed.

Step 4: Transfer and Top for Baking

• pasta mixture from Step 3
• 1/3 cup shredded cheddar cheese
• 1 cup seasoned croutons, crushed into bite-sized pieces

Preheat your oven to 375°F.

Pour the pasta mixture from Step 3 into a 9×13-inch baking dish, spreading it evenly.

Sprinkle the remaining 1/3 cup of shredded cheddar cheese over the top, then distribute the crushed croutons evenly across the surface.

I like to crush the croutons into bite-sized pieces rather than powder—this gives you pockets of texture instead of a thick crust, and they distribute more evenly throughout.

Step 5: Bake Until Golden and Bubbly

Place the baking dish in the preheated 375°F oven and bake for 15-20 minutes, until the top is golden brown and the edges are bubbling slightly.

Start checking at 15 minutes—the exact time depends on your oven.

The casserole is done when the cheese is melted and the croutons have turned a deep golden color.

Remove from the oven and let it rest for 2-3 minutes before serving to allow the sauce to set slightly.