In a medium bowl stir together the flours, ginger, baking soda, cinnamon, and salt; set aside. In a large bowl beat butter and sugar until light and fluffy. Add egg, molasses, and zest. Beat until smooth. Gradually beat in flour mixture until combined. Shape into 4 disks. Cover with plastic wrap and chill 4 hours or overnight.
Preheat oven to 350 degree F. On a lightly floured surface, working with one disk at a time, roll dough until it's 1/4-inch thick (if too firm, let stand 10 minutes). Cut out house shapes using a 3-inch cutter and arrange 2 inches apart on ungreased cookie sheets. Reroll scraps and repeat with remaining dough.
Bake for 8 to 9 minutes or until edges are firm and just starting to brown. Transfer to a wire rack and cool completely.
Decorate with cereal and candies, attaching with frosting. Makes about 60 3-inch cookies.