Start by bringing a large pot of salted water to a rolling boil. Add the macaroni and cook for about 8-10 minutes, stirring occasionally, until al dente. Drain and rinse briefly under cold water.

In a medium saucepan, melt the butter over medium heat. Whisk in the flour for 1-2 minutes. Gradually pour in the milk, whisking until thickened. Stir in the cheddar cheese until melted.

In a large mixing bowl, combine the cooked macaroni and diced ham. Pour the warm cheese sauce over the mixture and fold to combine.

Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish and transfer the macaroni mixture into it.

Mix panko breadcrumbs with melted butter and sprinkle over the macaroni mixture.

Bake in the preheated oven for 25-30 minutes until golden brown and bubbling.

Let it cool for about 5 minutes before serving to allow the cheese sauce to set.