HOW TO MAKE IT
Preheat the oven to 375°F.
Bring a large cast-iron cocotte of water to a boil, salt it, and cook the pasta according to the package instructions for al dente. Drain.
In a large cast-iron cocotte, melt the butter over medium heat. Add the flour and whisk until combined. Cook for 30 seconds, whisking constantly until a smooth paste forms. Add the milk and whisk until smooth. Bring to a boil, then reduce the heat and cook for 3 to 5 minutes, until the. mixture thickens and coats the back of a spoon. Add the nutmeg, pepper, triple crème and Gruyère cheeses, and thyme. Season with salt. Fold in the cooked pasta. Keep the mixture in the large cocotte for baking, or split it among 6 to 8 mini cocottes for individual portions.
In a small bowl, combine the Parmesan cheese, panko, and oil. Top the mac and cheese with the Parmesan mixture, place in the oven, and bake for20 to 30 minutes for the large cocotte or 20 to 25 minutes for the minis, until the top is golden brown and bubbling. Serve hot.