The gram cracker “gingerbread” houses are constructed ahead of time so the icing can dry and the house structure will be firm before the party. Royal icing is used for construction because it holds the parts firmly while constructing and also once dry.
The recipe I used called for two egg whites, 1/2 teaspoon cream of tartar, and 1 pound of powdered sugar. Beat the egg whites first until stiff and foamy. Then add the cream of tartar and powdered sugar and beat for a long time until stiff peaks form. Cover the unused icing with plastic wrap so no air will get to it. If it starts to dry it will become crunchy and clog up your decorating tips. Recipes for royal icing can also be found online.
Buying candy for the party is a lot of fun. I always look for small candies that can be used repeatedly on small houses.
Here are some examples of what the kids and adults made at our last party for Kevin and Melanie’s kids.
Decorating the yard is important too.