Delicious in its simplicity, this spin on classic tuna casserole includes our Four Cheese Tortellini for extra heartiness. Plus, it can be assembled ahead of time and baked whenever you’re ready for it.
1 tsp kosher salt
8 tbsp unsalted butter, divided
1 celery stalk, ¼” dice (about ½ cup)
1 medium onion, ¼” dice (about 2 cups)
16 oz button mushrooms, sliced
3 tbsp Armanino Creamy Garlic Sauce
½ cup all-purpose flour
3 cups chicken or vegetable stock, low sodium
2 ½ cups whole milk
1 cup frozen peas
2 (6-6.4 ounce) envelopes water-packed light tuna
1 lb Armanino Four Cheese Tortellini
1 cup shredded mild cheddar cheese
⅔ cup butter cracker crumbs (about 16-20 butter crackers)
Preheat the oven to 375°F. Coat a 4 quart baking dish with soft butter or cooking spray. Set aside.
Place the butter crackers in a ziploc bag and crush with a rolling pin to create fine crumbs. Set aside.
Melt 4 tablespoons of the butter in a large saucepan or Dutch oven over medium-high heat.
Add the onion, celery and a good pinch of salt; cook and stir until tender, about 5 minutes.
Add the mushrooms and continue to cook until softened and most of the liquid has evaporated, about 5-6 more minutes. Transfer the vegetables to a bowl, stir in the garlic sauce and set aside.
Return the pan to medium heat (no need to wash) and melt the remaining 4 tablespoons of butter.
Whisk in the flour and cook to a smooth paste, about 2 minutes.
Slowly whisk in the stock, milk and salt, and cook, stirring occasionally, until thickened, about 5 minutes. To prevent a lumpy sauce, add some of the liquid and whisk until smooth, slowly adding additional liquid and whisking until fully incorporated and lump free.
Remove the sauce from the heat. Add the tuna, breaking into bite size pieces, the cooked vegetable mixture and peas. Stir with a rubber spatula then gently fold in the frozen tortellini (no need to defrost or pre-cook). Taste and add more salt if needed.
Turn the mixture into the prepared baking dish and top with the grated cheese and cracker crumbs.
Bake until golden brown and bubbly, 20-25 minutes.
Cool for 5 minutes before serving to allow the sauce to thicken slightly. Serve hot.
Storage: Leftovers can be refrigerated in an airtight container for up to 3 days. The casserole is best reheated in a 350°F oven for around 10-15 minutes until warm and bubbly.
Make ahead: the casserole can be assembled and refrigerated a day in advance. Let the sauce cool fully before stirring in the tortellini. Add the cheese and breadcrumbs right before baking.
Pouch tuna tends to be a better quality but canned tuna can be substituted. Make sure it is water packed and drain it well.
Feel free to experiment with the toppings. Some like to use saltine crackers or even crushed potato chips for the butter cracker crust.