How to cook
Soak the potatoes for 20 minutes in cold water, then wash them very well under running water.
Cut them into large pieces and place them in a baking pan with water and oil and season them with salt.
Place the baking pan in a preheated 482°F (250 degree) oven and bake them for 30 minutes, while stirring them gently periodically.
Mix the mayonnaise with the grated yellow cheese and white cheese, add the milk and finely chopped parsley.
Stir and pour the mixture over the potatoes and bake them until they aquire a golden brown color.