Preheat the oven to 350°F.
Butter an 8-inch square cake pan.
Combine the dates and water in a small saucepan and cook until the dates are softened, about 10 minutes. Mash dates with a fork or potato masher and stir in baking soda and let it cool for 15 minutes.
In the bowl of an electric mixer, cream the brown sugar and butter until light and fluffy. Add the eggs, one at a time, mixing well between additions. Add the vanilla and orange zest and mix well. Scrape down the bowl.
Sift the flour and baking powder together and add salt. With the mixer turned off, add the dry ingredients and mix until just combined.
Add the cooled date mixture and mix well until combined. Transfer the batter to the prepared cake pan. Place a piece of paper towel in the center of a larger roasting pan and set the filled pan inside a roasting pan or. Fill the large pan with hot water until it reaches halfway up the sides of the cake pan. Cover the large pan tightly with aluminum foil. This creates a steam method for cooking the cake.
Bake the cake for 30 minutes. Remove the pan and let the cake cool for 15 minutes in the water bath, covered.
Whilst cake is baking, make caramel sauce. Place ½ cup of cream, sugar, corn syrup, maple syrup, butter and salt into a medium saucepan and stir well. Bring the mixture to a boil over medium-high heat. Whisk frequently for 15-25 minutes, until the mixture turns a golden chestnut brown color.
Add the remaining ½ cup of cream and whisk well to dissolve any lumps. Continue cooking over low heat for about 10 minutes, until deep golden brown. Remove from the heat.
Carefully lift the cake pan from the water bath, use a knife to release the cake from the sides of the pan if necessary. Invert the cake onto a cutting board.
Pour about half of the caramel sauce into the bottom of the pan. Using 2 large spatulas, return the cake to the pan, and pour the remaining sauce over the cake. Let the cake cool completely before serving or refrigerate for up to 3 days.
Cut into slices and serve with any extra caramel sauce.