Heat the oven: Preheat to 375°F (190°C). Grease a 9x13-inch baking dish or a similar casserole.

Cook the pasta: Bring a large pot of salted water to a boil. Cook pasta until just shy of al dente (1–2 minutes less than the package suggests). Drain and toss with a teaspoon of olive oil to prevent sticking.

Start the roux: In a large pot, melt 4 tablespoons butter over medium heat. Add flour and whisk for 1–2 minutes until it smells toasty and looks smooth. Don’t let it brown too much.

Build the sauce: Slowly whisk in milk and cream. Keep whisking to avoid lumps. Simmer gently for 5–7 minutes until it thickens enough to coat the back of a spoon.

Season the base: Stir in garlic, Dijon, hot sauce, onion powder, smoked paprika, 1 teaspoon salt, and several grinds of pepper. Taste and adjust now—seasoning the base makes the cheese sing later.

Add the cheese: Reduce heat to low. Stir in cheddar and Gruyère a handful at a time until smooth. Fold in half the Parmesan. If it seems too thick, splash in a bit more milk.

Combine with pasta: Add the drained pasta and toss until every nook is coated. The sauce should be slightly loose; it will tighten in the oven.

Make the topping: In a small skillet, melt remaining 2 tablespoons butter with 1 tablespoon olive oil over medium heat. Add panko and cook, stirring, until golden, 2–3 minutes. Stir in remaining Parmesan and a pinch of salt.

Assemble: Pour mac and cheese into the baking dish. Sprinkle the toasted panko evenly over the top. Add chopped herbs if using.

Bake: Bake 15–20 minutes until bubbling at the edges and the top is crisp. If you want extra color, broil for 1–2 minutes at the end, watching closely.

Rest and serve: Let it rest 5–10 minutes so the sauce settles. Scoop and serve hot.