To make the Royal Icing, put all ingredients in a mixing bowl and beat for 7-10 minutes or until icing holds a peak. (I have to admit, I do not always beat it to that point, and it still works fine.)
Next, put large spoonfuls of frosting in sandwich-size Ziploc baggies for building the houses.
Then, put a spoonful in a bag for each house for adding the candy.
When you are ready to build the houses, snip one edge of the baggies to pipe the icing out.
The icing will stay good in the bags left out on the counter for up to three days. When you need them, snip the edge of the baggies and start building.
Recipe by Real Life Dinner at https://reallifedinner.com/graham-cracker-gingerbread-houses-and-royal-icing-recipe/