Using a mixer fitted with the whisk attachment (or a hand mixer), BEAT the meringue powder, extract, and about half of the warm water until foamy (1-2 minutes).
ADD in the powdered sugar. Continue beating while slowly drizzling in the rest of the warm water. Stiff peaks will form in 7-10 minutes of beating on medium speed.
Slowly add more water 1 teaspoon at a time if the icing is too stiff. Slowly add more powdered sugar 1 Tablespoon at a time if the icing is too thin.
Rainbow Sprinkle Gingerbread House
Using an offset spatula, SPREAD the icing on the gingerbread house pieces. Dip into sprinkles. Let dry.
COVER the extra icing when not using to prevent it from crusting up. It can remain at room temperature as long as it is covered.
STIR in more powdered sugar if needed to create a sturdy construction icing. The consistency should be a little bit firmer than glue.
ASSEMBLE the gingerbread house. Add extra candies, cookies, and frosting as desired.
Notes
Don't be afraid to use a lot of icing while constructing the Rainbow Sprinkle Gingerbread House. When it dries, it will look like snow! You can also cover up any messy seams with more icing and candies when the house construction is finished.Use store-bought gingerbread men and gingerbread tree cookies, or bake our Grandma's Gingerbread Spritz recipe.