Preheat the oven to 425 F;
Cut up the cauliflower, mix with olive oil, salt and pepper, and place on baking sheet;
Roast the cauliflower for 20 minutes;
Cook the pasta according to instructions, but 2 minutes less than al dente (it will continue to cook with the sauce);
In a saucepan, melt the butter, add flour and create a roux;
Add one cup of milk at the time to the saucepan and mix well until fully incorporated;
Once all the milk is added, then let it cook and thicken up for a few minutes;
Take off the heat, add shredded Fontina, cubed brie and mix well until the cheeses are melted;
Add nutmeg and salt & pepper (taste for seasoning);
In a bowl, combine the Panko with Pecorino and thyme;
Spray 9x13" baking dish with cooking spray;
Add cauliflower and pasta to the baking dish and gently mix together;
Pour the sauce over and mix it again, to make sure that sauce is evenly distributed;
Sprinkle the dish with the Panko/Pecorino mixture on top and place into the oven for 20-25 minutes, until bubbly and golden brown;
Let it cool off slightly before serving. Enjoy!