Preheat the oven to 380*.
Grate five potatoes and one medium onion into a large mixing bowl.
In a saucepan, warm 1 cup cream and 1/4 cup water. Mix in salt, pepper, parsley, mustard, paprika, celery seed, bay leaf, cinnamon, cloves, allspice, nutmeg, cardamom, salt, mace, and ginger. Continue to cook on low for another ten minutes, then remove the bay leaf and pour over the grated potatoes.