Preheat your oven to 350°F and grease a 9x13-inch baking dish. Cook the macaroni according to package directions until al dente, then drain and set aside.
In a large pot over medium heat, melt the butter. Whisk in the flour and cook for 1-2 minutes, stirring constantly, until it forms a paste.
Gradually pour in the milk while whisking constantly to prevent lumps. Cook for 4-5 minutes until the sauce thickens.
Remove from heat and stir in the cheddar cheese, mozzarella, salt, garlic powder, and paprika until the cheese is completely melted and smooth.
Add the cooked macaroni to the cheese sauce and stir until well combined. Pour into the prepared baking dish.
Sprinkle panko breadcrumbs evenly over the top and bake for 20-25 minutes until bubbly and golden on top.
Let it cool for 5 minutes before serving—this helps it set up nicely and prevents burnt tongues!