There are many ways to make this. Having the right icing for gingerbread construction is key. You want it to be able to support your structure and hold the walls up. Make sure you use grease free utensils. I try to avoid anything that is plastic because sometimes it holds the grease. I have included a link to a Youtube video for you to watch that is an excellent tutorial on Royal Icing.
Course Miscellaneous
Ingredients
1st Recipe
3Tablespoonsmeringue powderor may use one egg white
4cupspowdered sugar
6Tablespoonswarm water
2nd Recipe
3wholeegg whitesroom temperature
4cups powdered sugar
1/2teaspooncream of tartar
Instructions
1st Recipe
This recipe makes about 3 cups. Beat all ingredients until icing forms peaks (7 to 10 minutes with a heavy duty mixer, 10 to 12 minutes at high speed with a hand held mixer). Keep all utensils completely grease free or it will fall apart. For a stiffer icing, use 1 Tablespoon less water. Cover with cold wet cloth.