Place 1 1/2 cups royal icing in a pastry bag fitted with a small plain tip. Starting with 1 side wall, pipe an outline on cookie, and make window openings. "Flood" the cookie by making zigzags of icing inside the outlined area, leaving windows unfilled. Smooth icing with a skewer or toothpick. Let set for 2 minutes.

Immediately sift peppermint dust over cookie, coating icing completely. Blow off excess dust from window openings. Repeat with remaining side wall and 2 pointed side walls, making a door opening and a round window opening on each of the pointed side walls, leaving door and window unfilled. Let pieces stand until set, at least 4 hours or overnight.

Pipe 2 parallel lines of royal icing onto roof (add more to bag if necessary). Attach 2 overlapping rows of candy wafers on the rounded bottom edge of each roof piece. Swoop seven-minute frosting on remaining part of each roof piece using an offset spatula. Immediately sprinkle with sugar. Let stand until set, about 4 hours.

Tint 1/2 cup of remaining royal icing with red gel-paste food coloring. Place in a pastry bag fitted with a small plain tip. Outline and fill in 1 round window with white royal icing. Immediately pipe concentric circles of red icing inside window, and drag arching lines from the center to the edges of the window in a spiral pattern using a toothpick or skewer. Repeat with remaining round window.

Outline and fill in 1 door with white royal icing. Immediately pipe horizontal lines of red icing across door, and drag a vertical line down from the top left to the bottom left of the door using a toothpick or skewer. For next line, drag from the bottom to the top of the door. Continue dragging lines through the icings, alternating up and down. Repeat with remaining door.

Outline and fill in both windows on 1 side wall with white icing. Immediately pipe several small dots of red icing inside windows, and drag lines through dots to swirl. Repeat with both windows of remaining side wall. Let pieces stand until windows and doors are set, at least 4 hours or overnight.

Cut 4 peppermint candy sticks to the height of a door. Attach sticks to sides of doors using icing or house glue. Cut 2 peppermint candy sticks a little longer than the width of a doorway. Attach 1 stick to top of each door using icing or house glue. Cut 8 peppermint candy sticks to the width of a side-wall window. Attach sticks to tops and bottoms of windows using icing or glue. Attach 1 diamond licorice candy "shutter" to each side of side-wall windows, using icing or glue. Attach halved round peppermint candies around edge of each round window using icing or house glue. Let wall pieces stand until candies are set, at least 4 hours or overnight.

Place glue in a pastry bag fitted with a medium plain tip. Pipe lines into an L shape onto a cake stand or serving platter, about the width of 2 side walls. Place base of 1 pointed side wall on stand, with bottom edge on line of glue. Pipe glue up left or right side, and attach a side wall, with bottom edge on line of glue. Hold walls together in place until somewhat set, about 2 minutes. Repeat with remaining 2 walls, gluing them to cake stand and walls and holding until somewhat set.

Reinforce walls by piping glue inside the house at the joints. Let stand until set, about 4 hours or overnight.

Pipe lines of glue onto the top edges of house. Attach 1 roof piece, laying it on the icing seams. Hold in place until somewhat set, about 2 minutes. Place a can or glass under the bottom of roof edge. Repeat with other side of roof. Let stand overnight.

Halve 4 licorice twists lengthwise. Pipe strips of glue around the top and side edges of pointed side walls. Cut 2 licorice twists to the height of the wall from the base to the bottom of the roof. Attach to glue strips. Repeat on other pointed side wall. Cut 2 more licorice twists to fit from the base of the roof to just under the eaves. Attach to glue strips. Repeat on other pointed side wall.

Pipe a line of glue or icing along the top roof seam, and place several peppermint candy balls in a row. Pipe icicles onto front edges of roof. Sprinkle sugar "snow" around base of house. Assemble snowmen by stacking white peppermint candy rings, large and small peppermint candy balls, and red gumballs using icing or glue between each. Top with sliced gumdrops or candy-coated chocolate candies, or cinnamon candies as hats. Place in "snow" around house. (Decorated house can be stored at room temperature for up to 2 weeks.)