Use graham crackers as backing to make the walls more sturdy, if desired.
Ensure you have royal icing to hold together your house. To make your own, beat 1 egg white with an electric mixer on high speed until foamy. Gradually add 2 cups confectioners’ sugar and ½ tsp. water and beat on high until stiff peaks form. Multiple batches may be needed.
Build each part of the Haus separately on a flat work surface or sheet pans lined with parchment paper, let dry completely, then assemble and decorate.