Preheat the oven to 350 degrees F. Grease an 8 by 8-inch cake pan and line with parchment paper. Grease and flour the pan.
Place the rum and raisins in a small pan, cover and heat until the rum boils. Turn off the heat and set aside. Place the butter and molasses in another small pan and bring to a boil over medium heat. Pour the mixture into the bowl of an electric mixer fitted with the paddle attachment. Cool for 5 minutes, then mix in the sour cream and orange zest.
Meanwhile, sift the flour, baking soda, ginger, cinnamon, cloves, and salt together in a small bowl. Mix with your hands until combined. With the mixer on low speed, slowly add the flour mixture to the molasses mixture and mix only until smooth. Drain the raisins and add them and crystallized ginger to the mixture with a spatula. Pour into the prepared pan and bake for about 35 minutes, until a toothpick comes out clean. Set aside to cool completely.
When the cake has cooled, whisk together the confectioners' sugar and orange juice and pour it onto the gingerbread, allowing it to drip down the sides. Allow the glaze to set. Cut the gingerbread into 9 squares.
Recipe courtesy of Ina Garten