Amish Chicken Casserole

Bring a large pot of lightly salted water to a boil. Cook egg noodles at a boil, stirring occasionally, until tender yet firm to the bite, 6 to 8 minutes. Drain and set aside.

While egg noodles are cooking, preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.

Melt butter in a medium saucepan over low heat. Gradually add flour, stirring until smooth. Cook, stirring constantly, for 1 minute. Gradually stir in chicken broth and milk. Increase heat to medium and cook and stir until mixture is bubbling and slightly thickened, 5 to 7 minutes. Remove sauce from the heat and stir in salt and pepper.

Combine reserved egg noodles, cooked chicken, and mushrooms in a large bowl. Add sauce and stir until combined. Spoon mixture into the prepared baking dish and sprinkle with Parmesan cheese.

Bake, uncovered, in the preheated oven until thoroughly heated, about 20 minutes.