1) Preheat the oven to 350°F. Grease a 9" x 13" pan, and flour it with gluten-free flour.
2) Whisk together the cake mix, spices, and baking soda.
3) In a separate bowl, beat the butter with half the cake mix/spices.
4) Beat in the molasses, vinegar, and one of the eggs.
5) Add the remaining eggs one at a time, beating well after each addition.
6) Add the buttermilk alternately with the remaining dry mix, one-third of each at a time. Beat until smooth, scraping the bowl after each addition.
7) Pour the batter into the prepared pan.
8) Bake the gingerbread for 40 to 45 minutes, until it's brown and firm on top. Its internal temperature should be between 210°F and 212°F.
9) Remove the cake from the oven, and cool it on a rack for 15 minutes before slicing.
Yield: one 9" by 13" cake.