Start with a double-layer square cake. (Avoid a recipe with pudding, so that you won't need to refrigerate this lofty project.) Ice the cake with white or stone-colored icing. Then, using decorator icing squeezed from tubes, adhere ice cream cone towers and turrets, mini marshmallows, cookie and candy details, and outline windows. Graham crackers and string licorice make a great drawbridge! Before the icing sets completely, sprinkle on multicolored sugar crystals for a magical touch. Glue paper pennants on toothpicks and insert these at the highest points.
Adapted from The Parents Party Book: Fun and Fabulous Theme Birthday Parties for Children 2 to 8 Years Old by the Editors of Parents Magazine. Golden Books, New York.