Preheat your oven to 375°F (190°C) and lightly grease a cast-iron skillet.
Cook the macaroni pasta according to the package instructions until al dente. Drain and set aside.
In a large skillet, cook the bacon over medium heat until crispy. Remove the bacon from the skillet and set aside, leaving the rendered bacon fat in the skillet.
In the same skillet, melt the butter in the bacon fat over medium heat. Add the flour and whisk until smooth to create a roux.
Gradually whisk in the milk, ensuring there are no lumps. Continue to whisk until the sauce thickens and coats the back of a spoon.
Reduce the heat to low and add the cheese blend, stirring until melted and smooth.
Crumble the cooked bacon and add it to the cheese sauce, mixing well.
Add the cooked macaroni pasta to the skillet and stir until the pasta is evenly coated in the cheese sauce.
In a separate bowl, melt some butter and mix it with the breadcrumbs until well combined.
Sprinkle the breadcrumb mixture evenly over the macaroni and cheese in the skillet.
Place the skillet in the preheated oven and bake for 15-20 minutes, or until the top is golden and the cheese is bubbly.
Remove from the oven and let it cool for a few minutes before serving.