Martha Stewart Chicken Tetrazzini

Coarse salt and ground pepper
6 tablespoons butter
1 pound white mushrooms, trimmed and sliced 1/4 inch thick
1/2 cup all-purpose flour
3 cups milk
1 can (14.5 ounces) reduced-sodium chicken broth
3/4 cup dry white wine (I used white grape juice as a substitute)
1.5 cups grated Parmesan cheese
1.5 cups grated cheddar cheese
1/2 teaspoon dried thyme leaves
1 pound linguine, broken in half
1 rotisserie chicken, skin removed, meat shredded (about 4 cups)
1/2 package (10 ounces) frozen peas, thawed and drained

Preheat oven to 400. Bring a large pot of salted water to a boil (for pasta). In a large saucepan, melt 2 tablespoons butter over high heat. Add mushrooms, and season with salt and pepper. Cook, tossing frequently, until tender and browned, 8 to 10 minutes. Transfer to a bowl, and set aside.

Make sauce: In same saucepan, melt remaining 4 tablespoons butter over medium heat. Add flour; cook, whisking, about 1 minute. Whisking constantly, gradually add milk, broth, and wine/white grape juice. Bring to a boil; reduce to a simmer, and add parmesan, cheddar cheese and thyme. Season with salt and pepper.

Cook pasta 2 minutes less than package instructions for al dente; drain and return to pot. Add sauce, chicken, peas, and mushrooms. Toss well to combine. Divide between two shallow 2-quart baking dishes; sprinkle with remaining Parmesan. Freeze (see below) or bake until browned, about 30 minutes. Let stand 10 minutes before serving.