Decorate sides of house. Using red FoodWriter marker, add words, trees and snowflakes to side panels of gingerbread house.
Prepare buttercream following recipe instructions. Tint icing red following color formulas provided. Prepare decorating bag with coupler and red icing. With tip 5, pipe seams of house. Switch to tip 1; pipe words on sides of house. Switch to tip 1S; pipe trees and snowflakes on side of house.