Step by step

Method

4 steps

1. 1

   Heat the oven to 375°F. Cook 12 oz spaghetti or linguine until just al dente; drain and set aside. Don't rinse — the starch helps the sauce cling.

2. 2

   In a large skillet, melt 3 tablespoons butter over medium heat. Sauté 8 oz sliced mushrooms and 1 small diced onion until the mushrooms are browned and the onion is soft, 6–8 minutes. Stir in 3 tablespoons flour and cook 1 minute. Whisk in 2 cups chicken broth and 1 cup milk; simmer until thickened and spoon-coating, 3–5 minutes.

3. 3

   Pull off heat. Stir in ½ cup sour cream, ½ teaspoon garlic powder, half the cheeses (¾ cup mozzarella/Jack + ¼ cup Parmesan), 3 cups cooked shredded chicken, ½ cup frozen peas if using, plus salt and pepper. Toss with the pasta until every strand is coated.

4. 4

   Spread in a greased 9×13-inch dish. Top with the remaining cheeses. Bake 20–25 minutes until bubbly at the edges and the top is golden in spots. Rest 5 minutes. You want creamy mushroom pasta under a golden cheesy top — not a dry underbaked bake or a broken watery sauce.