• Preheat oven to 325 degrees. Grease a 9 inch round or square pan and set it aside. (I used a 9-inch springform pan and it worked great)
• In a large bowl or kitchen aid mixer, cream butter and sugar until light and fluffy. Beat in molasses and egg until blended together.
• In a separate bowl combine the flour, baking soda, ginger, cinnamon, and salt; add to creamed mixture alternately with the water.
• Pour the cake into the 9-inch pan. Bake for 35-40 minutes or until the toothpick in the center comes out clean. Place on a wire rack.

To make the caramel sauce:

• In a medium-size saucepan, combine brown sugar and cornstarch. Add the water and bring to a boil until the sauce starts to thicken for about 2 minutes. This is not a thick sauce, so it will be fairly runny. Remove from heat and stir in the cubed butter and vanilla until melted and smooth. Serve over warm cake with whipped cream.