In a large mixing bowl, whisk together the flour, salt, baking powder, baking soda and spices to combine; set aside. In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter and sugar on medium-high speed until light and fluffy, about 2 minutes. Mix in the molasses and egg until combined. Add in the dry ingredients and mix just until incorporated. Cover the bowl and chill the dough for at least one hour.
Preheat the oven to 350° F. Line baking sheets with parchment paper. Roll the dough out on a lightly floured work surface to about ¼-inch thickness. Cut into desired shapes with cookie cutters. Place the cookie shapes onto the prepared baking sheets, about 2 inches apart. Bake for 10 minutes, rotating the pans halfway through baking. Remove from the oven and let cool on the baking sheets for 10 minutes. Transfer to a wire cooling rack and let cool completely. Decorate as desired.