Baked Buffalo Macaroni & Cheese

Arrange a rack in the middle of the oven and heat the oven to 375°F.

Bring a large pot of salted water to a boil. Add the macaroni and boil according to package directions. Drain.

Meanwhile, shred 1 pound cheddar cheese on the large holes of a box grater (about 4 cups). Melt 3 tablespoons unsalted butter in a medium saucepan over medium-high heat. Add 3 tablespoons all-purpose flour and cook, stirring constantly, until lightly toasted, about 1 minute. While stirring, slowly pour in 3 cups whole milk and bring to a boil. Continue to boil, stirring often, until thickened enough to coat the back of a spoon, about 6 minutes.

Reduce the heat to low and add the cheese, one handful at a time, stirring until each addition is melted before adding the next. Add the macaroni, 1/2 cup Frank's RedHot sauce, and 3 cups shredded, cooked chicken, if using, and stir to combine. Taste and season with more kosher salt as needed. Transfer to a 2-quart baking dish, or use a 3-quart or 9x13-inch baking dish if using chicken.

Place 4 tablespoons unsalted butter in a medium microwave-safe bowl and microwave until just melted, about 30 seconds. Add 1 1/2 cups panko breadcrumbs and 1 (1-ounce) packet ranch dip, and stir until well combined. Sprinkle the panko mixture evenly over the macaroni and cheese.

Bake until the top is golden-brown and the mac and cheese is bubbling, about 30 minutes. Let cool slightly. Meanwhile, pick the leaves from a few sprigs of fresh parsley if desired and finely chop. Sprinkle over the macaroni and cheese before serving.