Preheat oven to 375 degrees F
In a saucepan, melt 6 Tbsp of butter. When butter begins to bubble, stir in flour and cook for 1 minute. Slowly add milk and whisk until mixture begins to bubble and thicken.
Remove the saucepan from heat and stir in salt, pepper, nutmeg, cheddar cheese, gruyere and Melinda’s truffle hot sauce until melted and well incorporated. Set aside.
Bring the pot of water to a boil and cook elbow macaroni to the manufacturer’s directions. Once cooked, drain and rinse with cold water. Stir macaroni into the cheese sauce.
Fill two 9” cast iron pans with the macaroni and sprinkle with remaining cheddar and gruyere cheese along with breadcrumbs if desired. Bake for 30 minutes until golden on top.
Allow to cool and serve with more truffle hot sauce if desired!