Ingredients

• 12 ounces penne
• 2 tablespoons (1/4 stick) butter
• 2/3 cup sliced shallots (about 5)
• 1 pound mushrooms, sliced
• 2 tablespoons chopped fresh thyme
• 1 1/2 cups turkey gravy (preferably homemade)
• 1 1/2 cups (packed) coarsely grated Gruyère cheese (about 6 ounces), divided
• 1/2 cup whipping cream
• 3 cups diced cooked turkey meat (about 1 pound)

Instructions

1. Position rack in top third of oven; preheat to 350°F. Butter 13x9x2-inch glass or ceramic baking dish. Cook pasta in large pot of boiling salted water until tender but still firm to bite. Drain.
2. Melt 2 tablespoons butter in large nonstick skillet over medium-high heat. Add shallots; sauté 1 minute. Add mushrooms and thyme; sauté until mushrooms are tender and dark brown, about 12 minutes. Add pasta, gravy, 1 cup cheese, and cream to mushroom mixture; stir to blend. Mix in turkey. Season to taste with salt and pepper. Transfer to prepared baking dish. Sprinkle with remaining 1/2 cup cheese. Bake gratin until sauce is bubbling around edges and tips of pasta are golden brown, about 25 minutes. Let stand 5 minutes and serve.