This old-fashioned tuna noodle casserole is made without condensed soups and has an irresistible crunchy potato chip topping. Perfect for a homey family dinner.
Preheat the oven to 350°. Spray a small casserole dish (I used a 5x8" dish with 2" sides) with vegetable spray and set aside.
Bring a pot of water to a boil, add 1 teaspoon of salt to the water and pour in the pasta. Cook the pasta 1-2 minutes shy of al dente according to package directions (the pasta will continue to cook in the oven). Drain the macaroni and set aside.
Heat a large heavy skillet over medium high heat. When the pan is hot, spray with nonstick vegetable spray and add the mushrooms. Cook, stirring occasionally until the mushrooms brown and give up their liquid. Transfer to a bowl and set aside.
In the same skillet, heat the olive oil and butter over medium-high heat. Add the onions and celery and saute until tender and slightly translucent. Add garlic and cook until fragrant.
Sprinkle the flour, remaining ½ teaspoon kosher salt, mustard and oregano over the vegetables and stir constantly for one minute. Gradually add the milk, stirring constantly and bring to a boil. Cook for one minute or until the sauce thickens.
Remove the pan from the heat and add the tuna fish, and peas, mixing until evenly distributed with the sauce.
Add the cooked macaroni to the tuna and sauce and gently fold together to blend. Add 1½ cups of the grated cheese and fold into the tuna and noodle mixture.
Spread the tuna in the prepared casserole dish and sprinkle with the remaining cheese. Crumble the potato chips over the casserole (if using). Bake for 20-25 minutes or until bubbly and lightly browned.
Notes
Store leftovers in the refrigerator, well-wrapped. Heat leftovers at 350° for 10-15 minutes.