Cook the elbow macaroni according to the package instructions until al dente. Drain and set aside.

Prepare a casserole dish by greasing it with non-stick cooking spray. Preheat the oven to 350°F (175°C).

In a large pot or Dutch oven, melt 4 tablespoons of unsalted butter over medium heat.

Stir in the all-purpose flour and cook for another few minutes to remove the taste of the flour.

Whisk in the chicken or vegetable stock, stirring constantly until the mixture thickens.

Stir in the kosher salt, white pepper, and paprika.

Whisk in the heavy cream and continue stirring until the sauce thickens.

Reduce the heat to low and add the shredded Parmesan, Monterey Jack, and most of the shredded cheddar cheese (reserve ½ cup). Stir until the cheeses are fully incorporated and the sauce is smooth and creamy.

Add the cooked elbow macaroni to the cheese sauce, stirring until all the noodles are evenly coated.

Transfer the mac and cheese mixture to the prepared casserole dish, spreading it out evenly.

Top the mac and cheese with the remaining ½ cup of shredded cheddar cheese.

In a small bowl, mix together the melted salted butter and plain panko breadcrumbs.

Sprinkle the breadcrumb mixture evenly over the top of the mac and cheese.

Bake in the preheated oven for 25-30 minutes, or until the top is golden and bubbly.

Remove from the oven and allow it to cool for a few minutes before serving. Enjoy!