Preheat oven to 400 degree fahrenheit
In a large saucepan on medium heat, melt the butter. Once the butter is melted, add the flour. Cook for 2 minutes on medium
After 2 minutes, add in the milk, salt, pepper, and spice and cook for 3-5 minutes until warm and slightly thickened
After it is slightly thickened, add in the cheddar and gruyere cheese and spinach cook until the cheese has melted. Set aside
Butter a 9x13” baking pan and set aside
Slice the potatoes in 2 mm rounds. Fan them in 3 even rows long ways in the prepared baking dish
Pour over the cheese and spinach sauce
Tightly wrap with foil and bake for 1 hour
After 1 hour, remove the foil. Top with parmesan cheese and bake for 20 more minutes until golden
