- Heat the oven to 325 degrees and grease and flour a 9-inch square baking pan.
- In a large mixing bowl, combine the flour, ginger, cinnamon, baking soda, and salt.
- In a separate bowl, stir together the butter, brown sugar, molasses, egg, and hot water.
- Add this mixture to the dry ingredients and beat with an electric mixer on medium speed for about a minute, scraping the sides of the bowl with a rubber spatula.
- Pour the batter into the pan and bake it for about 40 minutes, until a toothpick inserted in the center comes out clean.
- Serve with whipped cream, if desired.