Preheat the oven to 350 degrees. Mix the flour, ginger, cinnamon, and baking soda in a bowl.
Cream the butter and brown sugar together, then add the molasses and egg. Combine the wet and dry mixtures until a dough forms.
Roll the dough to 1/4 inch thickness on a floured surface. Cut out house walls, roof pieces, and a base. Bake on lined sheets for 10 minutes until firm. Cool completely.
Beat the powdered sugar, meringue powder, and 3 tablespoons water until stiff peaks form. Tint half the icing black with food coloring.
Pipe white icing along the edges to assemble the walls and roof on the base. Let the structure set for 10 minutes.
Use the black icing to draw windows and cracks on the house. Attach the chocolate cookies upright in front as tombstones.
Melt the green candy melts and drizzle around the tombstones to create grass patches. Place mini marshmallows near the tombstones as ghosts.