A simple, beautiful project, building a sugar cube castle can be a great craft for any time of year, unlike gingerbread houses, which are very much connected to the Christmas season. Also, while they are safe to eat, sugar cubes are not nearly as appetizing as gingerbread so more of your building materials will remain with your project instead of in the project maker’s stomach. Just be careful not to eat too much of the icing or you will have to get more in order to finish.
Prepare your base. It is best to use some kind of heavy paper or cardboard for your base, especially if you are going to have to move your castle following its construction. You can glue your first layer directly to the base itself or allow it to remain freestanding at your discretion. This project uses a 40 by 40 cm (approximately 15 inch by 15 inch) square section of heavy cardboard covered with aluminium foil.
Create your sugar cube base by arranging a single layer of cubes in an 20 cm by 20 cm (8 inch by 8 inch) square (approximately 15 to a side). Leave a 7-cube gap for your door. You can glue these down if you want, but it is not required.
Build your layers. Use icing to hold the castle together. A cake decorator’s bag makes applying the icing very easy. You can support the tops of your windows and door by using heavy-duty paper, or by turning some cubes lengthwise and icing them into the sides to help support the weight. When you are placing your cubes, you can line them up so that the lines go straight up and down, or you can interlock them by placing them on the line. If you chose to go with the interlock method, be aware you may have to cut your cubes at ends of the wall, so this method is more complicated.
Create your battlements. To create the illusion of battlements, put a cube on top of every other or every third cubes.
Add towers. You can build your towers out from the sides of your castle by essentially adding squares at the corners. Build your towers to be slightly taller than your primary walls. Then you can build battlements at the tops of your towers the same as you did for the walls for uniformity of look.
Allow your castle to sit for a couple of hours without moving it to let the icing harden.
Other sweets can be used to provide decorations. Another easy way to add colour is to use coloured frosting. If you do not think icing will be sturdy enough, you can use glue. Putting a votive candle down inside the castle produces a very pretty golden glow. Be careful, of course, if you do, since this adds an element of danger to the project.