And here's the recipe...
1 c Powdered sugar
1 T Ener-G egg replacer (dry)
1 t Cream of tartar
1/8 t Xanthan gum
2 T Water (approximately)
Blend all dry ingredients together. Add water slowly until desired consistency is reached. Less water will be strong enough to bind gingerbread houses, more water will be better for a piping bag.