Cook the pasta: Bring a large pot of salted water to a boil. Cook the macaroni until just shy of al dente, about 1 minute less than the package suggests. Drain and set aside. Toss with a drizzle of oil if you’re worried about sticking.

Warm the dairy: In a small saucepan or microwave-safe cup, gently warm the milk and cream. Warm liquids blend more smoothly into the roux and help prevent lumps.

Make the roux: In a large saucepan over medium heat, melt 3 tablespoons of butter. Whisk in the flour and cook, whisking constantly, for 1 to 2 minutes. It should smell slightly toasty, not raw.

Build the sauce: Slowly whisk in the warm milk and cream, a splash at a time at first, until smooth. Continue whisking until the sauce thickens to coat the back of a spoon, 4 to 6 minutes. Reduce heat to low.

Temper the egg: In a small bowl, whisk the egg. Ladle in about 1/2 cup of the hot sauce in a thin stream while whisking constantly to warm the egg gently. Then whisk the tempered egg back into the sauce. This prevents scrambling.

Add seasonings and cheese: Stir in Dijon, garlic powder, smoked paprika, a good pinch of salt, and several grinds of black pepper. Remove from heat and stir in cheddar, Monterey Jack/Gruyère, and half the Parmesan until melted and smooth.

Combine with pasta: Add the drained pasta to the sauce and stir until every piece is coated. Taste and adjust seasoning. It should be slightly saltier than you think; the pasta will continue to absorb flavor.

Assemble: Pour into a greased 9x13-inch baking dish. Mix panko with melted butter and the remaining Parmesan. Sprinkle evenly over the top. Dust lightly with smoked paprika if you like.

Bake: Bake at 350°F (175°C) for 20 to 25 minutes, until bubbling at the edges and lightly golden on top. For extra color, broil for 1 to 2 minutes, watching closely.

Rest and serve: Let the mac and cheese rest 5 to 10 minutes before serving. This helps it set and scoop cleanly while staying creamy inside.