a hearty bechamel based baked dish loaded with tons of flavour!
Lightly grease a 10 cup dish and set it aside
Preheat your oven to 400 degrees F
Melt the butter in a large pot or dutch oven on medium heat.
Sprinkle in the flour, stirring constantly until it starts looking a little darker and has an almost nutty aroma - 2 minutes
Gradually add the three cups of milk, whisking constantly to ensure there are no lumps
The sauce will start to thicken and bubble (stir frequently so it doesn't burn)
Add in the onions, green chillies, nutmeg, pepper, and stock.
Mix well and cook to thicken - another 3-5 minutes
Fold in your chicken, potatoes and corn and take it off the heat
Stir in 1.5 cup of the cheese and then if your sauce is too thick looking add a little of the reserved milk until you get the right consistency. It should be thick enough to easily scoop up with a piece of bread.
SEASON! Because salt varies with stock and cheese wait till the end to season the dish. You want the dish to be a smidge more salty because the potatoes will suck up a little of the salt.
Pour into your pan, scatter over the remaining cup of cheese and bake for 8-10 minutes, can broil for another 2 to get crispier cheese.
Make ahead tip: If you're making this ahead of time then bake it 375 degrees uncovered for 25-30 minutes to ensure it gets heated the whole way through.
A note on the ingredient ranges: for a chunkier casserole use the larger amounts and for a lighter one dial it back a little.
for the chicken you can boil half a chicken breast and shred it, use leftover rotisserie chicken, etc
1 ½ cups of sliced potatoes is about 2 4-5 inch potatoes. I prefer to use yellow fleshed potatoes if you have them handy.