Preheat the oven to 375°F (190°C). Grease a 9x13-inch baking dish.
Boil a large pot of salted water. Add pasta and cook until just under al dente (1–2 minutes less than package). Drain and set aside.
In a saucepan, melt 4 tbsp butter over medium heat.
Whisk in ¼ cup flour. Cook for 1–2 minutes, stirring constantly.
Slowly add 2 cups warm milk and 1 cup cream. Whisk until smooth.
Cook for 3–5 minutes until the sauce thickens. Lower the heat.
Stir in 2 cups cheddar, 1 cup mozzarella, Dijon mustard (optional), garlic powder, onion powder, salt, and pepper. Mix until melted and smooth.
Add the pasta to the sauce. Stir until evenly coated.
Pour the pasta mixture into the baking dish.
Sprinkle the remaining 1 cup cheddar on top.
In a small bowl, mix 1 cup panko breadcrumbs, 2 tbsp melted butter, ¼ cup Parmesan, and smoked paprika (optional).
Sprinkle the breadcrumb mixture evenly over the pasta.
Bake for 20–25 minutes until golden and bubbly.
For extra crispiness, broil for 1–2 minutes (watch carefully).
Let cool for 5 minutes. Serve warm and enjoy!