Using a sharp knife or a mandoline, slice potatoes into rounds, about ¼ inch (6 mm) thick and discard the ends. Soak in cold water for about 10 minutes, drain then dry with a tea towel, place in bowl, add cream, shallot, garlic, salt and pepper. Toss until potatoes are coated. Grease a 9 x 9" casserole pan, layer potato slices, pressing to ensure there are no gaps, pour remaining cream on top and add parmesan cheese. Bake at 350°F (180°C), covered for the first 30 minutes then uncover and finish cooking for another 45 minutes, or until the potatoes are fork tender. Let rest until the dish has firmed, about 20 minutes. Cut and serve.