Bring a large pot of salted water to a rolling boil over high heat. Add elbow macaroni and cook for 7-8 minutes until al dente. Drain well and set aside.

In a medium saucepan over medium heat, melt 4 tablespoons butter until bubbly. Whisk in flour continuously for 1-2 minutes until the mixture turns golden.

Gradually pour in the milk while whisking constantly to prevent lumps. Continue whisking for 4-5 minutes until the mixture thickens enough to coat the back of a spoon.

Remove the pan from heat and stir in the shredded cheddar cheese, salt, and pepper. Keep stirring until cheese is completely melted and sauce is smooth.

Add the drained pasta to the cheese sauce and fold gently until every piece is coated. Transfer to a greased 9x13-inch baking dish and spread evenly.

Mix panko breadcrumbs with 2 tablespoons melted butter, then sprinkle across the top. Bake at 350°F for 20-25 minutes until edges are bubbling and breadcrumb topping turns golden brown. Let rest for 5 minutes before serving.