01 - Preheat the oven to 350°F. Grease a 9 x 13 inch baking dish.
02 - Boil elbow macaroni in salted water until just al dente, about 1 minute less than package instructions. Drain and set aside.
03 - Melt 4 tablespoons unsalted butter in a large saucepan over medium heat. Whisk in flour and cook for 1 to 2 minutes without browning.
04 - Gradually whisk in 3 1/3 cups whole milk until smooth. Simmer for 3 to 4 minutes until slightly thickened.
05 - Remove from heat. Stir in sharp cheddar, Gruyère, Dijon mustard, garlic powder, onion powder, salt, and black pepper until cheese melts and sauce is smooth.
06 - Mix cooked macaroni thoroughly with cheese sauce. Transfer to prepared baking dish.
07 - Combine panko breadcrumbs, melted butter, Parmesan cheese, and paprika in a small bowl. Evenly sprinkle over macaroni.
08 - Bake for 25 to 30 minutes until the topping is golden and sauce is bubbly.
09 - Allow to rest for 5 minutes before serving.