This creamy tuna noodle casserole has no dairy at all, and you’d never guess it. Elbow macaroni and flaky tuna bake in a silky plant-based sauce made with almond milk and nutritional yeast. It tastes rich and cheesy without milk, butter, or cheese.

It’s a great fit for anyone who avoids dairy, and it feeds four in about 55 minutes. With a gluten-free pasta and flour blend, it can be gluten-free too.

Why This Dairy-Free Casserole Works

Most tuna casseroles rely on canned cream soup or a milk and butter sauce. Here, olive oil and flour form the base of the sauce, and plant milk thickens into a smooth gravy. Cooking the onion first in the oil gives the sauce a sweet, savory backbone.

Nutritional yeast is the star. It’s a flaky yellow seasoning with a nutty, cheesy taste. Just two tablespoons make the sauce taste like it has Parmesan in it. Garlic powder and onion powder round out the flavor.

Ingredients and Easy Swaps

• Elbow macaroni: 12 ounces. Use a gluten-free brand if needed. Egg noodles also work if you eat eggs.
• Olive oil: 2 tablespoons. Avocado oil or dairy-free butter work too.
• Yellow onion: 1 small, finely chopped. A shallot gives a milder flavor.
• Flour: 2 tablespoons all-purpose or a gluten-free blend.
• Plant milk: 2 cups unsweetened almond milk. Oat milk makes a creamier sauce. Avoid vanilla or sweetened kinds.
• Nutritional yeast: 2 tablespoons. Find it in the health food aisle or spice section.
• Seasonings: Garlic powder, onion powder, salt, and pepper.
• Tuna: Two 5 ounce cans, drained and flaked.
• Frozen peas: 1 cup, optional.
• Dairy-free shredded cheese: ½ cup, optional, for the top.

How to Make It at a Glance

1. Cook the macaroni according to the package and drain.
2. Soften the onion in olive oil for about 4 minutes.
3. Stir in the flour for 1 minute, then slowly whisk in the almond milk.
4. Add the nutritional yeast and seasonings and whisk 3 to 5 minutes until slightly thick. Take off the heat and stir in the tuna and peas.
5. Mix with the pasta, spread in a greased 9×13 inch dish, and add the cheese if using.
6. Bake at 375°F for 20 to 25 minutes until hot and bubbly.

Common Mistakes to Avoid

Expecting the sauce to be very thick on the stove. Plant milk sauces thicken less than dairy ones. It only needs to coat a spoon lightly. It firms up more in the oven.

Using sweetened milk. Even “original” almond milk often has sugar. Check for “unsweetened” on the carton.

Skipping the nutritional yeast. Without it, the sauce tastes flat. It’s the ingredient that makes this taste cheesy.

Overcooking the pasta. Drain it a minute early, since it softens more as it bakes.

Variations

• Crispy topping: Toss ½ cup panko (or gluten-free crumbs) with a tablespoon of olive oil and sprinkle on top.
• Add veggies: Sauté sliced mushrooms or diced celery with the onion.
• Lemon and dill: Stir a teaspoon of lemon zest and a little fresh dill into the sauce.
• Chicken version: Use 2 cups shredded cooked chicken in place of the tuna.

What to Serve With It

A crisp green salad with a simple oil and vinegar dressing pairs well. Roasted carrots, steamed green beans, or sautéed zucchini add color. For a heartier meal, serve warm crusty bread with olive oil for dipping.

Make Ahead, Storage, and Reheating

Make ahead: Assemble the casserole, cover, and chill for up to 24 hours. Bake a few minutes longer since it starts cold.

Storage: Leftovers keep in the fridge in a sealed container for up to 3 days.

Reheating: Stir in a splash of almond milk, then warm in the microwave or in a covered dish at 350°F until heated through.

FAQ

What does nutritional yeast taste like?
It’s savory, a little nutty, and slightly cheesy. It’s not the same as baking yeast and won’t make anything rise.

Can I use a different plant milk?
Yes. Oat milk and soy milk both work well. Skip coconut milk, which adds a sweet coconut flavor.

Is it gluten-free?
It is if you use gluten-free pasta and a gluten-free flour blend.

Can I freeze it?
Yes, for up to 2 months. Thaw overnight in the fridge and add a splash of milk when reheating.

Is this casserole egg-free?
Yes, as long as you use elbow macaroni and not egg noodles. Most dried pasta is made without eggs, but check the label.

Can I add more cheesy flavor?
Add another tablespoon of nutritional yeast and a pinch of mustard powder to the sauce.

Tips for the Best Results

• Chop the onion very fine so it melts into the sauce.
• Whisk the almond milk in slowly, about ½ cup at a time, for the smoothest sauce.
• Taste the sauce before adding the tuna. Add more salt or garlic powder if needed.
• Let the casserole rest 5 minutes after baking so the sauce sets a little.

Choosing Dairy-Free Cheese

Dairy-free shreds melt very differently by brand. Some get creamy, while others stay in shreds. Cover the dish with foil for the first 10 minutes of baking to help them melt. The topping is optional, so you can skip it and add a crunchy breadcrumb layer instead.

Budget Tips

Nutritional yeast seems pricey, but one container lasts a long time. Store-brand almond milk works just as well as name brands. Canned tuna and dry pasta are low cost staples, so this casserole stays affordable.