A cardboard box cut to the size of the gingerbread house's interior forms the middle of the house. Frosting spread on the sides of the box hold the walls rigidly and permanently in place. No need to wait for it to dry before decorating!
Here is a side view of the roof piece, attached to a bent piece of cardboard. A toothpick through both of them holds them rigidly together.
This shows half the roof piece, with two small holes (drilled with a skewer) through which toothpicks are pushed to hold it to a piece of cardboard to reinforce the roof. Even without the roof decoration the toothpicks are nearly invisible. With frosting or candy, they are totally invisible.
The cardboard support with one piece of gingerbread is laid in place on the roof peak. The gingerbread piece is wider than the cardboard, to make it invisible once in place.
Here is the fully decorated house, using "Wheat Thin" crackers as shingles, melted blue "gummy bear" candies to make the water for the pond, and inverted ice cream cones coated with green frosting to make the evergreen trees. It is impossible to tell from the outside that there is cardboard reinforcing the house structure. Plus, we were read to decorate it within 20 minutes of starting - an important consideration when you've got impatient kids!
Another angle on our super gingerbread house. Notice the white frosting along the seam totally covers any sign that there is cardboard supporting the structure.
Closeup of the house, as well as the igloo (made from a dinner roll surrounded by mini-marshmallows) and a snowman made from full size marshmallows.
