Warm molasses in a saucepan or microwave, but do not boil just to soften. Remove from heat and stir in butter until melted. Let cool.
In a large bowl, whisk together flour, baking powder, salt, baking soda, ginger, cinnamon, and brown sugar.
Add butter mixture and egg and mix well. Refrigerate at least one hour until dough becomes stiff enough to roll.
Preheat oven to 350 degrees F. Line cookie sheets with parchment paper or Silpats.
Divide dough in half. Place each half between sheets of plastic wrap and roll out to a thickness of 1/8 to 1/4-inch thick. I also roll in between sil pads. And I find just rolling out on a slip pad is easy. Refrigerate one half while you roll out the other half, so dough is kept cold.
Dip the plastic cookie cutter in flour and cut shapes. I found without the flour was fine and had no problem with release from the metal cookie cutter. Place on prepared cookie sheets. Bake 12 to 15 minutes until lightly browned around the edges. Cool completely on wire racks, then decorate cookies as desired.
Roll out dough right onto the bottom side of cookie pan or on a edge free cookie pan that is lined with parchment. Maximum thickness for dough should be 3/8-inch. For houses larger than 6 inches square, use 1/4-inch thickness and for smaller houses, use 1/8-inch. Weight-bearing walls should be just slightly thicker. Place the template and cut house pieces using a ruler to guide for smooth straight edges. Bake for 15 minutes.