Pre-heat oven to 350°F. Grease a 9-inch spingform cake pan with butter and set aside.
In a stand mixer using the paddle attachment, combine egg, sugars, molasses, butter, and water and mix well. In a large bowl, whisk together flour, baking soda, ginger and salt. Slowly, add the flour mixture to the molasses mixture while mixing on low speed.
Evenly spread cranberries in the cake pan. Evenly pour the batter into cake pan, and bake for 40-50 minutes, or until toothpick is almost clean when inserted into the middle of the cake (you will have some crumbs, but not raw batter).
Remove from oven and allow the cake to slightly cool so you can handle the cake pan. Flip upside down and gently remove the springform.
* A regular 9-in cake can be used. I recommend lining the bottom with a circular piece of parchment paper to prevent the cake from sticking in the pan. *