This recipe can be multiplied as many times as necessary to feed a crowd.
The best results come from using a wide, shallow pan like a braiser or large skillet.
Please do not use pre-shredded cheese!
The mix of cheeses is up to you, but I like to use a blend of a flavorful cheese (sharp cheddar), a melty cheese (fontina, monterey jack, or similar), and a salty cheese (freshly grated parmesan). My ratio was 1 1/2 cups cheddar, 1 cup fontina and 1/2 cup freshly grated parmesan.
Feel free to add whatever mix-ins you like! Crispy bacon or caramelized onions would be delicious stirred in at the end.