In advance, make cookie message and doors: Roll out dough and cut two 4 1/4 x 1 1/4 in. door cookies. Tint portions of remaining dough red, green, yellow, blue and black; cut letters.
Thin a 1 1/2 in. ball of black dough with water to piping consistency; pipe tip 3 outlines on letters. Bake and cool all cookies. Attach letters to sticks with melted candy. Let harden.
Prepare four 1-layer 9 x 13 in. cakes for
stacked construction, placing a cake board, cut to fit, between upper and lower two cakes. Ice smooth.
Ice 1-layer 6 in. cake smooth and position on top. Mark 4 1/2 x 2 1/2 in. door area and 1 in. square window areas on 9 x 13 in. cakes, 3/4 in. square window areas on 6 in. cake. Pipe in areas with tip 3.
Outline all windows and door with tip 55; add tip 57 outline window sills on larger windows. Pipe tip 48 band building frames in corners.
Cover door cookies with tip 48 stripes; add tip 3 outline and dot handles. Attach to cake with icing. Pipe tip 44 outline door frame. Pipe tip 5 bead top and bottom borders on cakes.
Cut marshmallows in half. Position on cake board for shrubs and cover with tip 14 stars.
Insert cookie message, trimming sticks as needed. Tint shredded coconut green; position around building for grass. Position topper.
The star tip creates the most popular, easily accomplished decorations! The serrated edges of the star tip makes ridges in the icing as you squeeze it out. Use for borders, details such as buttons and facial features, flower centers, filling in cakes baked in shaped pans.