In a large bowl, whisk together flour, cocoa powder, baking soda and salt. Set aside. With an electric or stand mixer, cream together the butter, granulated sugar and brown sugar until light fluffy. Beat in egg, coffee or liqueur, and vanilla. Add in flour/cocoa mixture 1 cup at a time. Blend until fully incorporated. (If you are using a hand mixer you may need to add the last cup of flour by hand and work it in).
Divide dough into three large balls, place in a plastic bag and chill in the refrigerator 1-2 hours. Once chilled, work with one ball of dough at a time, and roll between 2 pieces of parchment paper. This prevents the dough from sticking to your rolling pin, and you don't need to add flour.
Cut out desired shapes with cookie cutters and place on a baking sheet lined with parchment paper. Bake cookies in a 350 degree oven for 7-9 minutes depending on size. Allow cookies to cool on baking sheet for a few minutes and then transfer to a wire cooling rack. Decorate as desired.