In a large casserole place a single overlapping layer of russet potatoes and apples. Sprinkle lightly with salt, pepper, nutmeg, marjoram, garlic, shallots and cheese.
Continue this layering process until the casserole is full and your final layer finishes with cheese topping.
Slowly pour the heavy cream over the dish, letting the cream fill the dish and come up over the top of the final layer of potatoes. You may want to press down gently on the top of the potatoes to make sure the final layer is submersed without being soupy.
Cover with foil and bake at 375° for 45 minutes or until potatoes are fork tender. Uncover and bake an additional 25-30 minutes or until the top is golden brown.