Make a paper pattern for your gingerbread house and get it printed, cut, and ready to go.

Preheat the oven to 360 degrees F (a little hotter than 350 degrees F helps the gingerbread to be crisper and sturdier.

Line a jelly roll pan with parchment. Use cooking spray to lightly grease the paper and the edges of the jelly roll pan. 

In a large bowl beat together the butter and brown sugar until light and fluffy. 

Add the egg and molasses and beat to combine.

Add the flour, ginger, baking soda, cinnamon, nutmeg, allspice, and salt and mix until the mixture comes together into a thick dough. 

Press the entire batch of dough into prepared pan in even layer.

Bake for 20 to 25 minutes or until a deep golden brown. 

Remove from the oven and let cool 5 minutes.

While still warm cut, place your paper pattern on top of the warm cookies slab, and out the desired shapes using a small paring knife.

Let the pieces cool completely in the pan and then run your knife through your cuts one last time.

Assemble cooled pieces using royal icing on a large carboard cake board and decorate with additional colored icing, with candy, marshmallow ghosts, or however you would like.

NOTE: this very large Halloween gingerbread house took 3 batches of gingerbread on three pans to make. The scraps of gingerbread leftover are delicious dipped in milk.