• Place the confectioner’s sugar, meringue powder and water into a large bowl and beat with an electric mixer for 10-14 minutes until the mixture is smooth and when drizzled, stays on the surface for a few seconds. If you find that the icing is too thick, gradually add a few more drops of water.
• Divide the mixture in half. One half will be used for the exterior of the house, and the other will be used for the wallpaper. Set the icing for the wallpaper aside, placing a sheet of plastic wrap directly onto the surface on the icing to prevent it from drying out.

Exterior of the House

• Place the white icing in a piping bag fitted with a small, round piping tip. Place the 3 exterior walls on a flat surface and pipe horizontal stripes about 1 cm apart onto all 3 walls. Then pipe short, vertical stripes between the stripes to create a brick pattern. Pipe window panes directly onto the pink candy windows. Allow the icing to set for about 30 minutes.
• Divide the remaining icing (for the exterior walls) into 6 bowls and dye them pink, orange, yellow, green, blue and purple. Place them into piping bags fitted with a round tip.
• Place the 2 roof cookies on a flat surface, and pipe a rainbow scallop pattern with all 6 colours, beginning with pink and ending with purple. Pipe shutters next to the windows on the exterior walls with the remaining pink icing by piping rectangles and filling them in. Allow these to fully set, then pipe little horizontal lines on top of the shutters with more pink icing to mimic the texture of shutters.
• Allow the roof and exterior walls to completely dry and harden to the touch, 4-6 hours or overnight. Transfer the remaining coloured icing into small bowls and place plastic wrap directly onto the surface of the icing to prevent them from drying out.

Interior of the House

• Once the icing on the exterior walls has fully set, flip the cookies over and place them on a sheet of parchment paper and a sheet of paper towel. This is to provide a soft surface for the piping on the exterior walls to rest on. Place the interior wall on a flat surface as well.
• Place the white icing for the wallpaper in a piping bag fitted with a small, round tip. Pipe a border of icing around the edges of the cookies and the windows. Allow the icing to set for about 30 minutes.
• Mix the remaining white icing with about 1-2 tbsp of water, until the icing is slightly runnier. Be careful not to add too much water. Return this runny white icing and the remaining coloured icing into individual piping bags. Working with one cookie at a time, fill the cookies with the runny white icing until the inside of the borders are completely filled. Before the icing has a chance to set, pipe on your desired pattern with the coloured icing. Piping on the coloured icing when the white icing is still wet will keep the icing flat and make it look like wallpaper. You could pipe on polka dots or stripes or whatever you like!
• If you’d like to add beadboard or any texture to the walls, allow the wallpaper to fully set for about 4 hours, then pipe vertical or horizontal stripes directly on top of the wallpaper. Allow the cookies to set overnight.