Preheat your oven to 400 degrees. Grease a baking dish with butter and set aside.
Place half of the potato slices in the buttered baking dish and set aside.
Melt butter in a saucepan and add flour. Whisk together.
Add milk, cream, and spices until thick.
Pour half the cream sauce over the potatoes, then add remaining potatoes and remaining cream. Cover with aluminum foil and bake for 45 minutes.
Remove foil, cover with cheeses and finish baking for 15 minutes or until top is golden brown.