Step 1: Cook the Pasta : Boil pasta in salted water until just al dente (slightly undercooked since it will bake). Drain and set aside.
Step 2: Make the Cheese Sauce : In a large saucepan, melt butter over medium heat. Whisk in flour to create a roux, cooking for 1–2 minutes until lightly golden. Slowly whisk in warm milk and cream until smooth. Simmer until thickened (about 5 minutes). Stir in cheddar, Gruyère, Parmesan, Dijon mustard, garlic powder, paprika, salt, and pepper until melted and smooth.
Step 3: Combine Pasta and Sauce : Add drained pasta to the sauce and stir until fully coated.
Step 4: Prepare the Topping : Mix panko breadcrumbs with melted butter, Parmesan, and parsley.
Step 5: Assemble and Bake : Pour mac and cheese into a greased 9x13-inch baking dish. Sprinkle breadcrumb mixture evenly over the top. Bake at 375°F (190°C) for 20–25 minutes, until golden brown and bubbly.
Step 6: Serve : Let cool for 5 minutes before serving.