In a medium bowl, mix together flour, cinnamon, ginger, salt, soda, and allspice. In the bowl of your mixer, beat vanilla, butter and sugar for about five minutes or until mixture is light and fluffy. Mixture will not be completely smooth. Beat in molasses and egg until blended and scrape down the side of the bowl once. Beat in flour mixture on low speed until well blended. Divide dough into 2 equal pieces and flatten each piece of dough into a circle. Wrap pieces in plastic wrap and refrigerate for at least two hours.
*Now let me insert here that I don’t eat my gingerbread houses. They are purely decoration. This being said, I use margarine instead of butter when I bake them. If I were going to make these into cookies I would use butter. But since I am making a good dozen and a half houses every Christmas, I go for the cheaper butter alternative and use margarine.
Frosting:
Mix all ingredients together until thick and firm. Scoop into frosting bags with rubber spatula. This will fill one frosting bag very full. (You can get disposable frosting bags at your favorite craft store in the cake decorating aisle. You may also use a ziplock like I did in the beginning, snipping off a corner. Be aware that you may end up with blowouts from the ziplock popping apart midway through decorating. Otherwise, these can be a good alternative in a pinch.)
Please note, you want your frosting to be very thick and cement like. You will get a VERY thick frosting from this recipe. If it is thinner, you will have trouble getting your house to stay together without holding it in place for a long time. If you would like your frosting to be a bit thinner, you can play around by adding more egg whites or sugar depending on the consistency you want.