Preheat oven to 400F

Peel and slice potatoes into 1/4 inch slices.

Place potatoes in large bowl and cover with 1 tbsp salt and 1 tbsp pepper. Mix to spread seasoning evenly oven potatoes.

Heat large skilet on medium heat. When skillet is hot add butter. When butter has melted, add in garlic. Cook for approximately 3 minutes flipping garlic occasionally. Be careful not to burn garlic. If garlic starts to brown go to next step and reduce heat a little.

Add in flour and heavy cream and whisk continuously for 30 seconds, then reduce heat to med-low. Continue to whisk for 5-10 minutes until you reach desired creaminess.

Add in Pecorrino or Parmesan, parsley, and remaining salt and pepper. Rurn stove off and stir well.

In large baking dish, arrange one layer of overlapping potato slices. Think of Solitaire with rows next to each other. Cover this layer with 1/3 of sauce from skillet. Repeat this for layers 2 and 3.

Cover with aluminum foil and bake for 1 hour.

Remove foil and bake for 20 minutes to brown the top.

Let this sit 10 minutes before serving.