Preheat oven to 375.
Grate cheese and set aside.
In a large saucepan, bring water and salt to a boil.
Boil pasta according to directions on box decreasing the time by about 2 min to assure you pasta is slightly undercooked.
Strain pasta, and return to the pot.
In a small skillet over medium heat add 2 tbsp butter and bread crumbs.
Stir for 2-3 minutes.
Turn off heat stir in 1 tbsp fresh parsley. Set aside.
In your cast iron skillet over medium heat melt the 6 tbsp of butter until bubbly.
Whisk in flour and until completely incorporated.
Whisk in milk and half-n-half.
Continue to stir until the mixture becomes thick and bubbly.
Once mixture is thick, lower heat, and stir in salt, pepper, and nutmeg.
Stir in cheese until melted.
Pour cheese mix over strained pasta, and mix well.
Pour back into Iron skillet.
Sprinkle bread crumb topping on.
Place in oven for 20-25 minutes.
When it's finished baking, I like to place under broiler on hi for 2-3 min.
When it comes out of the oven, garnish with remanding fresh parsley.