Preheat oven to 375. Wash peel and slice potatoes(whatever type of slice you prefer in AuGratin). Set aside. Prepare the sauce by melting 1/3 cup butter over med low heat. Add flour whisking continuously until flour is bubbly and slightly toasted. Pour in cold milk and whisk slowly. Adjust heat if necessary to allow the milk to come up to a low bubble and thicken. Add bouillon while sauce is thickening. Stir in all seasonings and cheese until melted and fully incorporated. Place potatoes in a large deep baking dish, pour sauce over potatoes and stir together. Cover tightly with foil and bake 30-45 minutes(depends on how thin you slice potatoes). Meanwhile prepare topping. Melt butter in microwave for 20 seconds, stir in panko and parmesean and set aside. Remove potatoes from oven, uncover and top with breadcrumbs, bake an additional 15 minutes until bubbly and crumb topping browns. Cook times vary widely due to the type and size of potato slices. Thicker slices or cubes may take up to 1 hour baking total. Just start checking for doneness after 30 minutes. Potatoes should be fork tender and sauce bubbly.